FKIE_CVE-2026-72193
Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-17 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ntfs3: cap RESTART_TABLE free-chain walker at rt->used
A crafted NTFS3 disk image triggers an in-kernel infinite loop at
mount time, hanging the mounting thread and firing the soft-lockup
watchdog within ~22s on multi-CPU hosts (panic with
kernel.softlockup_panic=1). The bug is reachable from desktop USB
auto-mount on distributions where udisks2 routes the NTFS signature
to the in-tree ntfs3 driver (Arch family and an increasing fraction
of Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual
mount elsewhere.
check_rstbl()'s second walker iterates the free-entry singly-linked
list headed by rt->first_free with no upper bound on iteration count:
for (off = ff; off;) {
if (off == RESTART_ENTRY_ALLOCATED)
return false;
off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off));
if (off > ts - sizeof(__le32))
return false;
}
The existing guards cover three exits: end-of-list (off == 0), the
in-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds
(off > ts - sizeof(__le32)). None of the three prevents an
in-bounds cycle.
A crafted on-disk RESTART_TABLE whose free chain contains a
self-loop or A->B->A cycle whose offsets satisfy:
- in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)]
- (off - sizeof(struct RESTART_TABLE)) % rsize == 0
passes all existing guards and spins the mount-time thread forever.
Reproduced in UML by hand-forging a 2 MB NTFS3 image whose journal
RESTART_TABLE first_free = 0x18 and whose entry at offset 0x18
stores 0x18 as its next pointer; mount of the forged image with
the in-tree ntfs3 driver never returns.
Bound the walker by rt->used. Each entry on a legitimate free
chain is unique, and the total slot count is ne = le16_to_cpu
(rt->used). A traversal that visits more than ne slots is by
construction malformed; reject it as a corrupt RESTART_TABLE.
After this patch, mount of the forged image returns with -EINVAL
and a log_replay failure message, and mkntfs-produced legitimate
images mount cleanly (verified in the same UML harness).
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": "8128bec895075253c779d67afdc90ae513265fca",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "7972df425687daa70d971fe6ed415e78683133dd",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "7ac4c86915c24c208a0f0611b71d9676686fe756",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "29b86dbe88cbbef53bb9aaec2e279359f8c450f8",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "0fad25687d4d3fa1fdd313d31b9cb5817c425029",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "d313416280d41bea272f02a6034dfa88008692a0",
"status": "affected",
"version": "b46acd6a6a627d876898e1c84d3f84902264b445",
"versionType": "git"
},
{
"lessThan": "9611f644302c07d21bc8af97e3e06a3d30064253",
"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",
"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\nntfs3: cap RESTART_TABLE free-chain walker at rt-\u003eused\n\nA crafted NTFS3 disk image triggers an in-kernel infinite loop at\nmount time, hanging the mounting thread and firing the soft-lockup\nwatchdog within ~22s on multi-CPU hosts (panic with\nkernel.softlockup_panic=1). The bug is reachable from desktop USB\nauto-mount on distributions where udisks2 routes the NTFS signature\nto the in-tree ntfs3 driver (Arch family and an increasing fraction\nof Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual\nmount elsewhere.\n\ncheck_rstbl()\u0027s second walker iterates the free-entry singly-linked\nlist headed by rt-\u003efirst_free with no upper bound on iteration count:\n\n for (off = ff; off;) {\n if (off == RESTART_ENTRY_ALLOCATED)\n return false;\n off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off));\n if (off \u003e ts - sizeof(__le32))\n return false;\n }\n\nThe existing guards cover three exits: end-of-list (off == 0), the\nin-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds\n(off \u003e ts - sizeof(__le32)). None of the three prevents an\nin-bounds cycle.\n\nA crafted on-disk RESTART_TABLE whose free chain contains a\nself-loop or A-\u003eB-\u003eA cycle whose offsets satisfy:\n\n - in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)]\n - (off - sizeof(struct RESTART_TABLE)) % rsize == 0\n\npasses all existing guards and spins the mount-time thread forever.\nReproduced in UML by hand-forging a 2 MB NTFS3 image whose journal\nRESTART_TABLE first_free = 0x18 and whose entry at offset 0x18\nstores 0x18 as its next pointer; mount of the forged image with\nthe in-tree ntfs3 driver never returns.\n\nBound the walker by rt-\u003eused. Each entry on a legitimate free\nchain is unique, and the total slot count is ne = le16_to_cpu\n(rt-\u003eused). A traversal that visits more than ne slots is by\nconstruction malformed; reject it as a corrupt RESTART_TABLE.\n\nAfter this patch, mount of the forged image returns with -EINVAL\nand a log_replay failure message, and mkntfs-produced legitimate\nimages mount cleanly (verified in the same UML harness)."
}
],
"id": "CVE-2026-72193",
"lastModified": "2026-08-17T06:18:19.947",
"metrics": {},
"published": "2026-08-15T06:21:37.797",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0"
}
],
"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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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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