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14 vulnerabilities found for FatFs 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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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