High 7.5Published Jun 24, 2026

CVE-2026-52957libceph: Fix potential null-ptr-deref in decode_choose_args()

Updated under an hour ago (Oct 27, 2026, 8:50 PM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential null-ptr-deref in decode_choose_args() A message of type CEPH_MSG_OSD_MAP contains an OSD map that itself contains a CRUSH map. When decoding this CRUSH map in crush_decode(), an array of max_buckets CRUSH buckets is decoded, where some indices may not refer to actual buckets and are therefore set to NULL. The received CRUSH map may optionally contain choose_args that get decoded in decode_choose_args(). When decoding a crush_choose_arg_map, a series of choose_args for different buckets is decoded, with the bucket_index being read from the incoming message. It is only checked that the bucket index does not exceed max_buckets, but not that it doesn't point to an index with a NULL bucket. If a (potentially corrupted) message contains a crush_choose_arg_map including such a bucket_index, a null pointer dereference may occur in the subsequent processing when attempting to access the bucket with the given index. This patch fixes the issue by extending the affected check. Now, it is only attempted to access the bucket if it is not NULL.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-476
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before d55ffad8d422b5d1cc44dad32bd3d25f4471cd9f; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before 301286c0ccd37d66b0e40786fd35a4f19cdbd88a; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before 7169f326a23d0f547fcd90e68b72fd387622e126; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before d7a65a34d2453f8cd3e0cc0e1319740af7e24276; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before 312ec973efac0efb9b9ed64214235910e9ecbaa8; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before f2f95e6d4b97e70bb876139b0583fc8079983f85; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before a20e16ebfe2fa65348eb4b2dc7deac330ce03e9c; from c7ed1a4bf4b446317eefa0f4916d94b1f6d3ada5 before 28b0a2ab8c82d0bbdeb8013029c67c978ce6e4bf	CNA record
linux linux_kernel linux:linux_kernel	from 4.13.1 before 5.10.258; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10; 4.13; and 7 more ranges	NVD

References

References

https://git.kernel.org/stable/c/d55ffad8d422b5d1cc44dad32bd3d25f4471cd9f	patch
https://git.kernel.org/stable/c/301286c0ccd37d66b0e40786fd35a4f19cdbd88a	patch
https://git.kernel.org/stable/c/7169f326a23d0f547fcd90e68b72fd387622e126	patch
https://git.kernel.org/stable/c/d7a65a34d2453f8cd3e0cc0e1319740af7e24276	patch
https://git.kernel.org/stable/c/312ec973efac0efb9b9ed64214235910e9ecbaa8	patch
https://git.kernel.org/stable/c/f2f95e6d4b97e70bb876139b0583fc8079983f85	patch
https://git.kernel.org/stable/c/a20e16ebfe2fa65348eb4b2dc7deac330ce03e9c	patch
https://git.kernel.org/stable/c/28b0a2ab8c82d0bbdeb8013029c67c978ce6e4bf	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.