Search
Find a vulnerability
Search criteria
14 vulnerabilities by ChaN
CVE-2026-6688 (GCVE-0-2026-6688)
Vulnerability from nvd – Published: 2026-07-01 14:01 – Updated: 2026-07-01 15:06
VLAI
Title
FatFs Buffer Overflow via Unbounded LFN Filename Copy
Summary
FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-120 - Buffer Copy without Checking Size of Input
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-long-fn-… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6688",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:06:55.618764Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:06:59.026Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-120",
"description": "CWE-120 Buffer Copy without Checking Size of Input",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:01:44.487Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-long-fn-of-downstream-cve-2026-6688/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Buffer Overflow via Unbounded LFN Filename Copy",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6688",
"datePublished": "2026-07-01T14:01:04.915Z",
"dateReserved": "2026-04-20T15:06:24.308Z",
"dateUpdated": "2026-07-01T15:06:59.026Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6687 (GCVE-0-2026-6687)
Vulnerability from nvd – Published: 2026-07-01 13:57 – Updated: 2026-07-01 15:06
VLAI
Title
FatFs Stack Buffer Overflow via Uncapped exFAT Label Length
Summary
FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-121 - Stack-based buffer overflow
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-exfat-la… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6687",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:06:20.995228Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:06:24.705Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-121",
"description": "CWE-121 Stack-based buffer overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:29.724Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Stack Buffer Overflow via Uncapped exFAT Label Length",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6687",
"datePublished": "2026-07-01T13:57:54.242Z",
"dateReserved": "2026-04-20T15:06:23.356Z",
"dateUpdated": "2026-07-01T15:06:24.705Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6686 (GCVE-0-2026-6686)
Vulnerability from nvd – Published: 2026-07-01 13:55 – Updated: 2026-07-01 15:05
VLAI
Title
FatFs Use of Uninitialized Clusters After Seek Past EOF
Summary
FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-908 - Use of uninitialized resource
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-uninit-c… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6686",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:05:23.138301Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:05:27.926Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"value": "FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "NONE",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-908",
"description": "CWE-908 Use of uninitialized resource",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T13:55:09.072Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-uninit-cluster-exposure-cve-2026-6686/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Use of Uninitialized Clusters After Seek Past EOF",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6686",
"datePublished": "2026-07-01T13:55:09.072Z",
"dateReserved": "2026-04-20T15:06:22.242Z",
"dateUpdated": "2026-07-01T15:05:27.926Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6685 (GCVE-0-2026-6685)
Vulnerability from nvd – Published: 2026-07-01 13:47 – Updated: 2026-07-01 15:26
VLAI
Title
FatFs Integer Underflow in Dirty-Sector Cache Flush
Summary
FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp->sect - sect < cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
6.1 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-191 - Integer underflow (wrap or wraparound)
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-unsigned… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6685",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:26:17.001634Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:26:37.612Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp-\u0026gt;sect - sect \u0026lt; cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp-\u003esect - sect \u003c cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 6.1,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-191",
"description": "CWE-191 Integer underflow (wrap or wraparound)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:51.392Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-unsigned-sub-wrap-cve-2026-6685/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Integer Underflow in Dirty-Sector Cache Flush",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6685",
"datePublished": "2026-07-01T13:47:25.764Z",
"dateReserved": "2026-04-20T15:06:21.250Z",
"dateUpdated": "2026-07-01T15:26:37.612Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6684 (GCVE-0-2026-6684)
Vulnerability from nvd – Published: 2026-07-01 13:45 – Updated: 2026-07-01 15:25
VLAI
Title
FatFs Infinite Loop in GPT Partition Scan
Summary
FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-835 - Loop with unreachable exit condition ('infinite loop')
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-gpt-scan… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6684",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:25:35.369745Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:25:53.071Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThan": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eFatFs prior to R0.16 that use GPT scanning with \u0027FF_LBA64 = 1\u0027 contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.\u003cbr\u003e\u003cbr\u003e\u003c/p\u003e"
}
],
"value": "FatFs prior to R0.16 that use GPT scanning with \u0027FF_LBA64 = 1\u0027 contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-835",
"description": "CWE-835 Loop with unreachable exit condition (\u0027infinite loop\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:58.544Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Infinite Loop in GPT Partition Scan",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6684",
"datePublished": "2026-07-01T13:45:03.639Z",
"dateReserved": "2026-04-20T15:06:20.061Z",
"dateUpdated": "2026-07-01T15:25:53.071Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6683 (GCVE-0-2026-6683)
Vulnerability from nvd – Published: 2026-07-01 13:41 – Updated: 2026-07-01 15:24
VLAI
Title
FatFs Divide-by-Zero in exFAT Sync
Summary
FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-369 - Divide by zero
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-exfat-di… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6683",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:24:38.147110Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:24:56.449Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"value": "FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-369",
"description": "CWE-369 Divide by zero",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:11:06.688Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Divide-by-Zero in exFAT Sync",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6683",
"datePublished": "2026-07-01T13:41:11.337Z",
"dateReserved": "2026-04-20T15:06:19.048Z",
"dateUpdated": "2026-07-01T15:24:56.449Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6682 (GCVE-0-2026-6682)
Vulnerability from nvd – Published: 2026-07-01 13:36 – Updated: 2026-07-01 15:24
VLAI
Title
FatFs Integer Overflow in FAT32 Volume Mount
Summary
In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs->n_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-190 - Integer overflow or wraparound
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-fat32-in… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6682",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:23:46.354718Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:24:05.860Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs-\u0026gt;n_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs-\u003en_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-190",
"description": "CWE-190 Integer overflow or wraparound",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:11:14.785Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-fat32-int-of-mnt-cve-2026-6682/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Integer Overflow in FAT32 Volume Mount",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6682",
"datePublished": "2026-07-01T13:36:59.935Z",
"dateReserved": "2026-04-20T15:06:18.243Z",
"dateUpdated": "2026-07-01T15:24:05.860Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6688 (GCVE-0-2026-6688)
Vulnerability from cvelistv5 – Published: 2026-07-01 14:01 – Updated: 2026-07-01 15:06
VLAI
Title
FatFs Buffer Overflow via Unbounded LFN Filename Copy
Summary
FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-120 - Buffer Copy without Checking Size of Input
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-long-fn-… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6688",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:06:55.618764Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:06:59.026Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-120",
"description": "CWE-120 Buffer Copy without Checking Size of Input",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:01:44.487Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-long-fn-of-downstream-cve-2026-6688/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Buffer Overflow via Unbounded LFN Filename Copy",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6688",
"datePublished": "2026-07-01T14:01:04.915Z",
"dateReserved": "2026-04-20T15:06:24.308Z",
"dateUpdated": "2026-07-01T15:06:59.026Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6687 (GCVE-0-2026-6687)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:57 – Updated: 2026-07-01 15:06
VLAI
Title
FatFs Stack Buffer Overflow via Uncapped exFAT Label Length
Summary
FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-121 - Stack-based buffer overflow
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-exfat-la… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6687",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:06:20.995228Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:06:24.705Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-121",
"description": "CWE-121 Stack-based buffer overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:29.724Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Stack Buffer Overflow via Uncapped exFAT Label Length",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6687",
"datePublished": "2026-07-01T13:57:54.242Z",
"dateReserved": "2026-04-20T15:06:23.356Z",
"dateUpdated": "2026-07-01T15:06:24.705Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6686 (GCVE-0-2026-6686)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:55 – Updated: 2026-07-01 15:05
VLAI
Title
FatFs Use of Uninitialized Clusters After Seek Past EOF
Summary
FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-908 - Use of uninitialized resource
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-uninit-c… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6686",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:05:23.138301Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:05:27.926Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"value": "FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "NONE",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-908",
"description": "CWE-908 Use of uninitialized resource",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T13:55:09.072Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-uninit-cluster-exposure-cve-2026-6686/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Use of Uninitialized Clusters After Seek Past EOF",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6686",
"datePublished": "2026-07-01T13:55:09.072Z",
"dateReserved": "2026-04-20T15:06:22.242Z",
"dateUpdated": "2026-07-01T15:05:27.926Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6685 (GCVE-0-2026-6685)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:47 – Updated: 2026-07-01 15:26
VLAI
Title
FatFs Integer Underflow in Dirty-Sector Cache Flush
Summary
FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp->sect - sect < cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
6.1 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-191 - Integer underflow (wrap or wraparound)
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-unsigned… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6685",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:26:17.001634Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:26:37.612Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp-\u0026gt;sect - sect \u0026lt; cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp-\u003esect - sect \u003c cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 6.1,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-191",
"description": "CWE-191 Integer underflow (wrap or wraparound)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:51.392Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-unsigned-sub-wrap-cve-2026-6685/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Integer Underflow in Dirty-Sector Cache Flush",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6685",
"datePublished": "2026-07-01T13:47:25.764Z",
"dateReserved": "2026-04-20T15:06:21.250Z",
"dateUpdated": "2026-07-01T15:26:37.612Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6684 (GCVE-0-2026-6684)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:45 – Updated: 2026-07-01 15:25
VLAI
Title
FatFs Infinite Loop in GPT Partition Scan
Summary
FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-835 - Loop with unreachable exit condition ('infinite loop')
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-gpt-scan… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6684",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:25:35.369745Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:25:53.071Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThan": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eFatFs prior to R0.16 that use GPT scanning with \u0027FF_LBA64 = 1\u0027 contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.\u003cbr\u003e\u003cbr\u003e\u003c/p\u003e"
}
],
"value": "FatFs prior to R0.16 that use GPT scanning with \u0027FF_LBA64 = 1\u0027 contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-835",
"description": "CWE-835 Loop with unreachable exit condition (\u0027infinite loop\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:10:58.544Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Infinite Loop in GPT Partition Scan",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6684",
"datePublished": "2026-07-01T13:45:03.639Z",
"dateReserved": "2026-04-20T15:06:20.061Z",
"dateUpdated": "2026-07-01T15:25:53.071Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6683 (GCVE-0-2026-6683)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:41 – Updated: 2026-07-01 15:24
VLAI
Title
FatFs Divide-by-Zero in exFAT Sync
Summary
FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Severity
4.6 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-369 - Divide by zero
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-exfat-di… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6683",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:24:38.147110Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:24:56.449Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"value": "FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 4.6,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-369",
"description": "CWE-369 Divide by zero",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:11:06.688Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Divide-by-Zero in exFAT Sync",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6683",
"datePublished": "2026-07-01T13:41:11.337Z",
"dateReserved": "2026-04-20T15:06:19.048Z",
"dateUpdated": "2026-07-01T15:24:56.449Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6682 (GCVE-0-2026-6682)
Vulnerability from cvelistv5 – Published: 2026-07-01 13:36 – Updated: 2026-07-01 15:24
VLAI
Title
FatFs Integer Overflow in FAT32 Volume Mount
Summary
In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs->n_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Severity
7.6 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-190 - Integer overflow or wraparound
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://www.runzero.com/blog/fatfs-bugs/ | third-party-advisory |
| https://github.com/runZeroInc/vulns-2026-fatfs-chance | technical-description |
| https://elm-chan.org/fsw/ff/ | product |
| https://www.runzero.com/advisories/fatfs-fat32-in… | third-party-advisory |
Date Public
2026-07-01 13:00
Credits
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-6682",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-01T15:23:46.354718Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T15:24:05.860Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "FatFs",
"vendor": "ChaN",
"versions": [
{
"lessThanOrEqual": "R0.16",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "HD Moore of runZero, Inc."
},
{
"lang": "en",
"type": "coordinator",
"value": "Tod Beardsley of runZero, Inc."
}
],
"datePublic": "2026-07-01T13:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs-\u0026gt;n_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"value": "In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs-\u003en_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "PHYSICAL",
"availabilityImpact": "HIGH",
"baseScore": 7.6,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-190",
"description": "CWE-190 Integer overflow or wraparound",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-01T14:11:14.785Z",
"orgId": "44488dab-36db-4358-99f9-bc116477f914",
"shortName": "runZero"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/blog/fatfs-bugs/"
},
{
"tags": [
"technical-description"
],
"url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
},
{
"tags": [
"product"
],
"url": "https://elm-chan.org/fsw/ff/"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.runzero.com/advisories/fatfs-fat32-int-of-mnt-cve-2026-6682/"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "FatFs Integer Overflow in FAT32 Volume Mount",
"x_generator": {
"engine": "Vulnogram 1.0.2"
}
}
},
"cveMetadata": {
"assignerOrgId": "44488dab-36db-4358-99f9-bc116477f914",
"assignerShortName": "runZero",
"cveId": "CVE-2026-6682",
"datePublished": "2026-07-01T13:36:59.935Z",
"dateReserved": "2026-04-20T15:06:18.243Z",
"dateUpdated": "2026-07-01T15:24:05.860Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}