NULL Pointer Dereference The advisory has been revoked - it doesn't affect any version of package kernel-headers (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL10-KERNELHEADERS-14453004
- published17 Dec 2025
- disclosed16 Dec 2025
Introduced: 16 Dec 2025
CVE-2025-40348 (opens in a new tab)Amendment
The Red Hat security team deemed this advisory irrelevant for RHEL:10.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by RHEL.
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
- https://bugzilla.redhat.com/show_bug.cgi?id=2422710
- https://access.redhat.com/security/cve/CVE-2025-40348
- https://git.kernel.org/stable/c/6ed8bfd24ce1cb31742b09a3eb557cd008533eec
- https://git.kernel.org/stable/c/7c34feda6a9a203c9744281f1b6671b7dad2012d
- https://git.kernel.org/stable/c/c7af5300d78460fc5037ddc77113ba3dbfe77dc0