slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-40348
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-16 14:15:46 UTC
Updated2026-10-14 13:10:00 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 715b6a5b41dae39baeaa40d3386b548bb278b9c2 c7af5300d78460fc5037ddc77113ba3dbfe77dc0 git Not specified
CNA Linux Linux affected 07e38a54cabd9b4de7ceb7f075f29ffa463e458a 7c34feda6a9a203c9744281f1b6671b7dad2012d git Not specified
CNA Linux Linux affected f7381b9116407ba2a429977c80ff8df953ea9354 6ed8bfd24ce1cb31742b09a3eb557cd008533eec git Not specified
CNA Linux Linux affected 6.12.54 6.12.56 semver Not specified
CNA Linux Linux affected 6.17.4 6.17.6 semver Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c7af5300d78460fc5037ddc77113ba3dbfe77dc0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6ed8bfd24ce1cb31742b09a3eb557cd008533eec 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7c34feda6a9a203c9744281f1b6671b7dad2012d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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