Vulnerability-Lookup

GHSA-2RJ4-34VW-Q254

Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-30 15:34

Details

In the Linux kernel, the following vulnerability has been resolved:

ntfs3: free the sbi after a grace period

If the "nocase" mount option ntfs3 uses custom hash and dentry compare functions. Both access ntfs3 superblock private information in rcu pathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any rcu delay. A lookup that's still inside the filesystem when the last reference to the mount is dropped causes a UAF. With a pathwalk held up in ntfs_d_hash() while the last reference to the mount goes away:

BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940 Read of size 8 at addr ff1100010453c850 by task walker/99 Call Trace: ntfs_nls_to_utf16+0x752/0x940 ntfs_d_hash+0x22b/0x500 link_path_walk+0x11ad/0x1d30 path_lookupat+0x63/0xb00 filename_lookup+0x1f1/0x5b0 vfs_statx+0xd7/0x3b0 [...] Allocated by task 95: __kmalloc_cache_noprof+0x249/0x560 ntfs_init_fs_context+0x2db/0x5a0 alloc_fs_context+0x52e/0xc70 [...] Freed by task 98: kfree+0x1db/0x5b0 deactivate_locked_super+0x9c/0xf0 cleanup_mnt+0x9f/0x130 task_work_run+0x131/0x250

The bug is currently masked by the grace period in namespace_unlock() for umount(2). Keep the necessary information until the filesystem private info is freed and free it with an rcu delay.

ntfs3_free_sbi() now runs from an rcu callback and drops the upcase table via ntfs_put_shared(). So switch s_shared_lock over to spin_lock_bh(). Otherwise the callback can deadlock against a task holding the lock on the same cpu.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99171"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T11:17:37Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: free the sbi after a grace period\n\nIf the \"nocase\" mount option ntfs3 uses custom hash and dentry compare\nfunctions. Both access ntfs3 superblock private information in rcu\npathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any\nrcu delay. A lookup that\u0027s still inside the filesystem when the last\nreference to the mount is dropped causes a UAF. With a pathwalk held up\nin ntfs_d_hash() while the last reference to the mount goes away:\n\n  BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940\n  Read of size 8 at addr ff1100010453c850 by task walker/99\n  Call Trace:\n   \u003cTASK\u003e\n   ntfs_nls_to_utf16+0x752/0x940\n   ntfs_d_hash+0x22b/0x500\n   link_path_walk+0x11ad/0x1d30\n   path_lookupat+0x63/0xb00\n   filename_lookup+0x1f1/0x5b0\n   vfs_statx+0xd7/0x3b0\n  [...]\n  Allocated by task 95:\n   __kmalloc_cache_noprof+0x249/0x560\n   ntfs_init_fs_context+0x2db/0x5a0\n   alloc_fs_context+0x52e/0xc70\n  [...]\n  Freed by task 98:\n   kfree+0x1db/0x5b0\n   deactivate_locked_super+0x9c/0xf0\n   cleanup_mnt+0x9f/0x130\n   task_work_run+0x131/0x250\n\nThe bug is currently masked by the grace period in namespace_unlock()\nfor umount(2). Keep the necessary information until the filesystem\nprivate info is freed and free it with an rcu delay.\n\nntfs3_free_sbi() now runs from an rcu callback and drops the upcase\ntable via ntfs_put_shared(). So switch s_shared_lock over to\nspin_lock_bh(). Otherwise the callback can deadlock against a task\nholding the lock on the same cpu.",
  "id": "GHSA-2rj4-34vw-q254",
  "modified": "2026-10-30T15:34:24Z",
  "published": "2026-10-28T12:31:06Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99171"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36e6753daf9bb64563dcb5a3bb22f7699d973fa2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7abecef26a9be8f9de70659a3092250461a52072"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c01b091b06412d3b1b53d8c2925f6de586c8a2fc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c39150784a801dbbfaf4fbfa284cb610552a5039"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8b1a4840467930e01f1a9374d991d7a8a2896c1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99171 (GCVE-0-2026-99171)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:35 – Updated: 2026-10-30 12:42

Title

ntfs3: free the sbi after a grace period

Summary

In the Linux kernel, the following vulnerability has been resolved: ntfs3: free the sbi after a grace period If the "nocase" mount option ntfs3 uses custom hash and dentry compare functions. Both access ntfs3 superblock private information in rcu pathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any rcu delay. A lookup that's still inside the filesystem when the last reference to the mount is dropped causes a UAF. With a pathwalk held up in ntfs_d_hash() while the last reference to the mount goes away: BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940 Read of size 8 at addr ff1100010453c850 by task walker/99 Call Trace: <TASK> ntfs_nls_to_utf16+0x752/0x940 ntfs_d_hash+0x22b/0x500 link_path_walk+0x11ad/0x1d30 path_lookupat+0x63/0xb00 filename_lookup+0x1f1/0x5b0 vfs_statx+0xd7/0x3b0 [...] Allocated by task 95: __kmalloc_cache_noprof+0x249/0x560 ntfs_init_fs_context+0x2db/0x5a0 alloc_fs_context+0x52e/0xc70 [...] Freed by task 98: kfree+0x1db/0x5b0 deactivate_locked_super+0x9c/0xf0 cleanup_mnt+0x9f/0x130 task_work_run+0x131/0x250 The bug is currently masked by the grace period in namespace_unlock() for umount(2). Keep the necessary information until the filesystem private info is freed and free it with an rcu delay. ntfs3_free_sbi() now runs from an rcu callback and drops the upcase table via ntfs_put_shared(). So switch s_shared_lock over to spin_lock_bh(). Otherwise the callback can deadlock against a task holding the lock on the same cpu.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6639 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/c39150784a801dbbf…
https://git.kernel.org/stable/c/36e6753daf9bb6456…
https://git.kernel.org/stable/c/c8b1a4840467930e0…
https://git.kernel.org/stable/c/7abecef26a9be8f9d…
https://git.kernel.org/stable/c/c01b091b06412d3b1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: a3a956c78efaa202b1d75190136671cf6e87bfbe , < c39150784a801dbbfaf4fbfa284cb610552a5039 (git) Affected: a3a956c78efaa202b1d75190136671cf6e87bfbe , < 36e6753daf9bb64563dcb5a3bb22f7699d973fa2 (git) Affected: a3a956c78efaa202b1d75190136671cf6e87bfbe , < c8b1a4840467930e01f1a9374d991d7a8a2896c1 (git) Affected: a3a956c78efaa202b1d75190136671cf6e87bfbe , < 7abecef26a9be8f9de70659a3092250461a52072 (git) Affected: a3a956c78efaa202b1d75190136671cf6e87bfbe , < c01b091b06412d3b1b53d8c2925f6de586c8a2fc (git)
Linux	Linux	Affected: 6.2 Unaffected: 0 , < 6.2 (semver) Unaffected: 6.6.161 , ≤ 6.6.* (semver) Unaffected: 6.12.115 , ≤ 6.12.* (semver) Unaffected: 6.18.59 , ≤ 6.18.* (semver) Unaffected: 7.2.13 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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      ],
      "cpeApplicability": [
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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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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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.
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