FKIE_CVE-2025-40348

Vulnerability from fkie_nvd - Published: 2025-12-16 14:15 - Updated: 2026-10-14 13:10
Severity
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6ed8bfd24ce1cb31742b09a3eb557cd008533eec
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7c34feda6a9a203c9744281f1b6671b7dad2012d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c7af5300d78460fc5037ddc77113ba3dbfe77dc0
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/slub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c7af5300d78460fc5037ddc77113ba3dbfe77dc0",
              "status": "affected",
              "version": "715b6a5b41dae39baeaa40d3386b548bb278b9c2",
              "versionType": "git"
            },
            {
              "lessThan": "7c34feda6a9a203c9744281f1b6671b7dad2012d",
              "status": "affected",
              "version": "07e38a54cabd9b4de7ceb7f075f29ffa463e458a",
              "versionType": "git"
            },
            {
              "lessThan": "6ed8bfd24ce1cb31742b09a3eb557cd008533eec",
              "status": "affected",
              "version": "f7381b9116407ba2a429977c80ff8df953ea9354",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/slub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.12.56",
              "status": "affected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
              "lessThan": "6.17.6",
              "status": "affected",
              "version": "6.17.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nslab: Evitar condici\u00f3n de carrera en slab -\u003e obj_exts en alloc_slab_obj_exts\n\nSi dos hilos competidores entran en alloc_slab_obj_exts() y uno de ellos falla al asignar el vector de extensi\u00f3n de objeto, podr\u00eda sobrescribir el slab -\u003e obj_exts v\u00e1lido asignado por el otro hilo con OBJEXTS_ALLOC_FAIL. Esto har\u00e1 que el hilo que perdi\u00f3 esta condici\u00f3n de carrera y espera un puntero v\u00e1lido desreferencie un puntero NULL m\u00e1s adelante.\n\nActualizar slab -\u003e obj_exts at\u00f3micamente usando cmpxchg() para evitar sobrescrituras de slab -\u003e obj_exts por hilos en condici\u00f3n de carrera.\n\nGracias por la ayuda de Vlastimil y Suren con la depuraci\u00f3n."
    }
  ],
  "id": "CVE-2025-40348",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {},
  "published": "2025-12-16T14:15:46.583",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6ed8bfd24ce1cb31742b09a3eb557cd008533eec"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7c34feda6a9a203c9744281f1b6671b7dad2012d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7af5300d78460fc5037ddc77113ba3dbfe77dc0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}



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