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Vulnerability record · CVE-2026-52957 · published 24 June 2026

CVE-2026-52957: Linux kernel null pointer dereference vulnerability

Linux · Linux Kernel

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.

7.5 CVSS 3.1 High EPSS 0.72% · top 48.1% CWE-476 · NULL pointer dereference
7.5CVSS 3.1 base score
0.72%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
14 Jul 2026Last modified by NVD

Description

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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Source: NIST National Vulnerability Database (record CVE-2026-52957), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.