FKIE_CVE-2026-64533
Vulnerability from fkie_nvd - Published: 2026-07-27 08:16 - Updated: 2026-07-30 06:25
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: validate lcns_follow in log_replay conversion
log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY
records when replaying version 0 restart tables.
During this conversion, the memmove() length is derived directly from
the on-disk lcns_follow field:
memmove(&dp->vcn, &dp0->vcn_low,
2 * sizeof(u64) +
le32_to_cpu(dp->lcns_follow) * sizeof(u64));
check_rstbl() validates restart table structure, but does not constrain
per-entry lcns_follow values relative to the entry size. A malformed
filesystem image can provide an oversized lcns_follow value, causing
the conversion memmove() to access memory beyond the bounds of the
allocated restart table buffer.
The same field is later used to bound iteration over page_lcns[],
so validating lcns_follow during conversion also prevents downstream
out-of-bounds access from the same malformed metadata.
Compute the maximum valid lcns_follow from the already-validated
restart table entry size and reject entries that exceed this bound.
Reuse the existing t16/t32 scratch variables already declared in
log_replay() to avoid introducing new declarations.
[almaz.alexandrovich@paragon-software.com: fixed the conflicts]
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs3/fslog.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ca343a99806b4fc8e27c48f08be3445c5fcd1445",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "ddfc8683e1a627dbf1b83bacf8961443dd654258",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "57c071e2c4f30b9c6f5aacb6679aab1269fbae99",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "159f694d682e4215b3822ae31ed3a4631628fe55",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "7adb38279812c9c06b0e3fa7382f4d7887f3fa2d",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "32b9f8733feb241627fa5f564b1a99b5cae974c5",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "6a4c53a2e26a865565bd6a460961e8d6fcb32329",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ntfs3/fslog.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate lcns_follow in log_replay conversion\n\nlog_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY\nrecords when replaying version 0 restart tables.\n\nDuring this conversion, the memmove() length is derived directly from\nthe on-disk lcns_follow field:\n\n\tmemmove(\u0026dp-\u003evcn, \u0026dp0-\u003evcn_low,\n\t\t2 * sizeof(u64) +\n\t\t\t\tle32_to_cpu(dp-\u003elcns_follow) * sizeof(u64));\n\ncheck_rstbl() validates restart table structure, but does not constrain\nper-entry lcns_follow values relative to the entry size. A malformed\nfilesystem image can provide an oversized lcns_follow value, causing\nthe conversion memmove() to access memory beyond the bounds of the\nallocated restart table buffer.\n\nThe same field is later used to bound iteration over page_lcns[],\nso validating lcns_follow during conversion also prevents downstream\nout-of-bounds access from the same malformed metadata.\n\nCompute the maximum valid lcns_follow from the already-validated\nrestart table entry size and reject entries that exceed this bound.\nReuse the existing t16/t32 scratch variables already declared in\nlog_replay() to avoid introducing new declarations.\n\n[almaz.alexandrovich@paragon-software.com: fixed the conflicts]"
}
],
"id": "CVE-2026-64533",
"lastModified": "2026-07-30T06:25:57.223",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-27T08:16:22.510",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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