CVE-2026-72196 (GCVE-0-2026-72196)
Vulnerability from cvelistv5
Published
2026-08-15 05:53
Modified
2026-08-17 05:41
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: bound copy_lcns dp->page_lcns[] index in analysis pass
In log_replay()'s analysis pass, after find_dp() returns a
valid DIR_PAGE_ENTRY for the (target_attr, target_vcn) tuple,
the copy_lcns block walks lrh->lcns_follow further entries:
t16 = le16_to_cpu(lrh->lcns_follow);
for (i = 0; i < t16; i++) {
size_t j = (size_t)(le64_to_cpu(lrh->target_vcn) -
le64_to_cpu(dp->vcn));
dp->page_lcns[j + i] = lrh->page_lcns[i];
}
find_dp() only validates that target_vcn falls within
[dp->vcn, dp->vcn + dp->lcns_follow), i.e., that the FIRST
cluster is covered. The walk through the further entries is
not bounded against dp->lcns_follow. For a malformed LRH
where target_vcn = dp->vcn + dp->lcns_follow - 1 and
lrh->lcns_follow > 1, the i > 0 writes overflow the dp's
allocated page_lcns[] array.
Add the missing j + lrh->lcns_follow <= dp->lcns_follow guard.
Reproduced under UML+KASAN on mainline 8d90b09e6741 as a
slab-out-of-bounds write of size 8 from log_replay+0x68d4 on
the mount path.
This is distinct from Pavitra Jha's 2026-05-02 patch
("fs/ntfs3: validate lcns_follow in log_replay conversion",
<20260502154252.164586-1-jhapavitra98@gmail.com>) which
addresses the separate version-0 dirty-page-table conversion
path's memmove(&dp->vcn, ...) call. The two fixes are
complementary; both should land.
[almaz.alexandrovich@paragon-software.com: clang-formatted the changes,
fixed conflicts]
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 |
||
{
"containers": {
"cna": {
"affected": [
{
"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": [
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{
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{
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"versionType": "git"
},
{
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{
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{
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"product": "Linux",
"programFiles": [
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],
"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": "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",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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{
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: bound copy_lcns dp-\u003epage_lcns[] index in analysis pass\n\nIn log_replay()\u0027s analysis pass, after find_dp() returns a\nvalid DIR_PAGE_ENTRY for the (target_attr, target_vcn) tuple,\nthe copy_lcns block walks lrh-\u003elcns_follow further entries:\n\n\tt16 = le16_to_cpu(lrh-\u003elcns_follow);\n\tfor (i = 0; i \u003c t16; i++) {\n\t size_t j = (size_t)(le64_to_cpu(lrh-\u003etarget_vcn) -\n\t le64_to_cpu(dp-\u003evcn));\n\t dp-\u003epage_lcns[j + i] = lrh-\u003epage_lcns[i];\n\t}\n\nfind_dp() only validates that target_vcn falls within\n[dp-\u003evcn, dp-\u003evcn + dp-\u003elcns_follow), i.e., that the FIRST\ncluster is covered. The walk through the further entries is\nnot bounded against dp-\u003elcns_follow. For a malformed LRH\nwhere target_vcn = dp-\u003evcn + dp-\u003elcns_follow - 1 and\nlrh-\u003elcns_follow \u003e 1, the i \u003e 0 writes overflow the dp\u0027s\nallocated page_lcns[] array.\n\nAdd the missing j + lrh-\u003elcns_follow \u003c= dp-\u003elcns_follow guard.\n\nReproduced under UML+KASAN on mainline 8d90b09e6741 as a\nslab-out-of-bounds write of size 8 from log_replay+0x68d4 on\nthe mount path.\n\nThis is distinct from Pavitra Jha\u0027s 2026-05-02 patch\n(\"fs/ntfs3: validate lcns_follow in log_replay conversion\",\n\u003c20260502154252.164586-1-jhapavitra98@gmail.com\u003e) which\naddresses the separate version-0 dirty-page-table conversion\npath\u0027s memmove(\u0026dp-\u003evcn, ...) call. The two fixes are\ncomplementary; both should land.\n\n[almaz.alexandrovich@paragon-software.com: clang-formatted the changes,\nfixed conflicts]"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.4,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flaw is in ntfs3 log_replay() during mount when parsing a crafted $LogFile on a block device; exploitation requires a local mount syscall or auto-mount of attacker-supplied removable media, not delivery through a network-facing kernel protocol handler.\nAC:L - An attacker fully controls malicious NTFS $LogFile journal fields (target_vcn, lcns_follow, page_lcns) and can craft the dirty-page-table state; KASAN reliably reproduced the slab OOB write on mount with no races or attacker-uncontrollable conditions.\nPR:N - No account or privileges on the victim are needed when a crafted NTFS volume on removable media is auto-mounted by udisks/systemd as root; alternatively an unprivileged user can trigger replay via user-namespace mount with CAP_SYS_ADMIN.\nUI:N - Once an attacker mounts or causes mount of a crafted NTFS image, log_replay() runs automatically inside ntfs_fill_super() with no further user interaction; the vulnerable copy_lcns path is reached during standard journal analysis on every affected mount attempt.\nS:U - Exploitation corrupts kernel heap memory during ntfs3 journal replay in the mounting process context; impact is privilege escalation within the same kernel/host security boundary, not a VM-guest-to-host or IOMMU boundary crossing.\nC:H - KASAN confirmed a slab out-of-bounds write of 8 bytes past dp-\u003epage_lcns[] in a kmalloc-backed DIR_PAGE_ENTRY; such heap corruption can overwrite adjacent slab objects and be groomed into arbitrary kernel memory read primitives.\nI:H - The bug is an out-of-bounds write into kernel heap metadata or adjacent objects beyond the allocated page_lcns[] array; per kernel guidance OOB writes enable controlled heap corruption paths toward arbitrary kernel writes and privilege escalation.\nA:H - KASAN reported slab-out-of-bounds write from log_replay() on mount; heap corruption during journal replay can cause immediate kernel oops/panic and is repeatable on each mount of a malicious NTFS volume, constituting high availability impact."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:41:23.012Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/9b3d8cc9d54fcded4de51b2b1026ae7182512077"
},
{
"url": "https://git.kernel.org/stable/c/9b7c28d8c61bdb041936222a09a708531a1c2921"
},
{
"url": "https://git.kernel.org/stable/c/0f13e823bf86bd1800168ea0bb5bca8b8500a81c"
},
{
"url": "https://git.kernel.org/stable/c/d240cd98f5f7b65c90f6b2b6abe3232ccdc405ab"
},
{
"url": "https://git.kernel.org/stable/c/49c86dae0c0ccb8d98ddcdc46987259389c816dd"
},
{
"url": "https://git.kernel.org/stable/c/5e7b598660cfa8e5af172cf4c65cffc126333307"
}
],
"title": "fs/ntfs3: bound copy_lcns dp-\u003epage_lcns[] index in analysis pass",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72196",
"datePublished": "2026-08-15T05:53:55.509Z",
"dateReserved": "2026-08-09T03:40:39.911Z",
"dateUpdated": "2026-08-17T05:41:23.012Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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