GHSA-33RW-P5M7-Q9C2
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32In 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).
{
"affected": [],
"aliases": [
"CVE-2026-72193"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:21:37Z",
"severity": null
},
"details": "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": "GHSA-33rw-p5m7-q9c2",
"modified": "2026-08-15T06:32:15Z",
"published": "2026-08-15T06:32:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72193"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
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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.