ghsa-468j-fmh4-69r9
Vulnerability from github
Published
2025-12-16 15:30
Modified
2025-12-16 15:30
Details

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

slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts

If two competing threads enter alloc_slab_obj_exts() and one of them fails to allocate the object extension vector, it might override the valid slab->obj_exts allocated by the other thread with OBJEXTS_ALLOC_FAIL. This will cause the thread that lost this race and expects a valid pointer to dereference a NULL pointer later on.

Update slab->obj_exts atomically using cmpxchg() to avoid slab->obj_exts overrides by racing threads.

Thanks for Vlastimil and Suren's help with debugging.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40348"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-16T14:15:46Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nslab: Avoid race on slab-\u003eobj_exts in alloc_slab_obj_exts\n\nIf two competing threads enter alloc_slab_obj_exts() and one of them\nfails to allocate the object extension vector, it might override the\nvalid slab-\u003eobj_exts allocated by the other thread with\nOBJEXTS_ALLOC_FAIL. This will cause the thread that lost this race and\nexpects a valid pointer to dereference a NULL pointer later on.\n\nUpdate slab-\u003eobj_exts atomically using cmpxchg() to avoid\nslab-\u003eobj_exts overrides by racing threads.\n\nThanks for Vlastimil and Suren\u0027s help with debugging.",
  "id": "GHSA-468j-fmh4-69r9",
  "modified": "2025-12-16T15:30:42Z",
  "published": "2025-12-16T15:30:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40348"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6ed8bfd24ce1cb31742b09a3eb557cd008533eec"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7c34feda6a9a203c9744281f1b6671b7dad2012d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c7af5300d78460fc5037ddc77113ba3dbfe77dc0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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