CVE-2026-72195 (GCVE-0-2026-72195)
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 attr_off in UpdateResidentValue against data_off
In do_action()'s UpdateResidentValue case (fslog.c:3307),
lrh->attr_off and lrh->redo_len come from the on-disk LRH.
When they satisfy aoff + dlen < attr->res.data_off, the
assignment
attr->res.data_size = cpu_to_le32(aoff + dlen - data_off);
underflows to ~4 GiB (e.g. 0xFFFFFFF9 when aoff=0x10, dlen=1,
data_off=0x18). Subsequent code that reads attr->res.data_size
to walk the resident attribute payload would then read up to
4 GiB past the 1024-byte MFT record allocation.
The existing mi_enum_attr() defense in fs/ntfs3/record.c:287
catches the corrupted data_size on the next attribute walk
and fails the mount, but only on the path that walks all
attributes. A read site that picks an attribute by name and
reads its data_size without re-validating is not covered.
Validate aoff against data_off and asize at the source.
Reproduced under UML+KASAN on mainline 8d90b09e6741 via
pr_warn-only probe: with aoff=0x10 and data_off=0x18, the
post-assignment data_size is 0xfffffff9 (mount then fails
at -22 from mi_enum_attr).
[almaz.alexandrovich@paragon-software.com: clang-formatted the changes]
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 Version: b46acd6a6a627d876898e1c84d3f84902264b445 |
||
{
"containers": {
"cna": {
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{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs3/fslog.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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"versions": [
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"version": "5.15"
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"version": "0",
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"version": "5.15.212",
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},
{
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"version": "6.1.178",
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},
{
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"status": "unaffected",
"version": "6.6.145",
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},
{
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"status": "unaffected",
"version": "6.12.97",
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},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
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{
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"status": "unaffected",
"version": "7.1.5",
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},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: bound attr_off in UpdateResidentValue against data_off\n\nIn do_action()\u0027s UpdateResidentValue case (fslog.c:3307),\nlrh-\u003eattr_off and lrh-\u003eredo_len come from the on-disk LRH.\nWhen they satisfy aoff + dlen \u003c attr-\u003eres.data_off, the\nassignment\n\n\tattr-\u003eres.data_size = cpu_to_le32(aoff + dlen - data_off);\n\nunderflows to ~4 GiB (e.g. 0xFFFFFFF9 when aoff=0x10, dlen=1,\ndata_off=0x18). Subsequent code that reads attr-\u003eres.data_size\nto walk the resident attribute payload would then read up to\n4 GiB past the 1024-byte MFT record allocation.\n\nThe existing mi_enum_attr() defense in fs/ntfs3/record.c:287\ncatches the corrupted data_size on the next attribute walk\nand fails the mount, but only on the path that walks all\nattributes. A read site that picks an attribute by name and\nreads its data_size without re-validating is not covered.\nValidate aoff against data_off and asize at the source.\n\nReproduced under UML+KASAN on mainline 8d90b09e6741 via\npr_warn-only probe: with aoff=0x10 and data_off=0x18, the\npost-assignment data_size is 0xfffffff9 (mount then fails\nat -22 from mi_enum_attr).\n\n[almaz.alexandrovich@paragon-software.com: clang-formatted the changes]"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The bug is reached only when the kernel mounts an attacker-controlled NTFS volume and replays $LogFile via ntfs_loadlog_and_replay\u2192log_replay\u2192do_action(UpdateResidentValue); exploitation uses the local mount syscall on a block/loop device, not a network-facing kernel service.\nAC:L - The attacker fully controls malicious on-disk LRH fields (attr_off, redo_len, data) in $LogFile; triggering the data_size underflow is deterministic once the crafted volume is mounted, with no races or conditions outside attacker control.\nPR:L - Mounting ntfs3 requires CAP_SYS_ADMIN in the mount namespace; an unprivileged local attacker can obtain this via user namespaces (unshare -Ur) and loop-mount a crafted NTFS image, without real root in the initial user namespace.\nUI:N - No victim interaction is required when the attacker mounts their own malicious NTFS image in a user namespace; exploitation does not depend on another user plugging in media, opening a file, or performing an additional action.\nS:U - The vulnerability corrupts kernel heap metadata during filesystem journal replay on the mounting host; impact stays within the kernel\u0027s security authority and does not constitute a VM escape, sandbox escape, or cross-authority boundary change.\nC:H - Unsigned underflow sets attr-\u003eres.data_size to ~4 GiB; subsequent resident-attribute consumers that trust data_size can read far beyond the ~1 KiB kmalloc MFT record allocation, disclosing adjacent kernel heap memory.\nI:H - The underflow corrupts resident-attribute metadata and UpdateResidentValue memmove paths using attacker-controlled offsets can overwrite attribute headers and drive out-of-bounds writes during replay, enabling heap corruption suitable for control-flow hijacking.\nA:H - Malformed journal replay can trigger kernel faults (KASAN/oops) or abort mount; repeated mount attempts against the malicious image cause persistent denial of service on the affected system."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:41:21.899Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ab8761676d638c5be170aaf91b7ffdd451236616"
},
{
"url": "https://git.kernel.org/stable/c/53c12f178f584dc5f836ffe2782138a6e9348ed9"
},
{
"url": "https://git.kernel.org/stable/c/546518468e6c9ea469669eef78f8cc380ad6e2ca"
},
{
"url": "https://git.kernel.org/stable/c/97758fd9756b5f09e9ddc6a5f6a569041acc8421"
},
{
"url": "https://git.kernel.org/stable/c/50b5e83384e7fed3d11d18b79ff350e9d6d89861"
},
{
"url": "https://git.kernel.org/stable/c/a89c66674283a0293c0f266dc57087a6114371a3"
},
{
"url": "https://git.kernel.org/stable/c/d1570c48f49a693974d000251030370ee2e83539"
}
],
"title": "fs/ntfs3: bound attr_off in UpdateResidentValue against data_off",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72195",
"datePublished": "2026-08-15T05:53:54.869Z",
"dateReserved": "2026-08-09T03:40:39.911Z",
"dateUpdated": "2026-08-17T05:41:21.899Z",
"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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