PT-2026-51851 · Linux · Linux

Published 2026-06-24 · Updated 2026-06-24 · CVE-2026-52957

Mitre

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.

Related Identifiers

CVE-2026-52957

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-52957 · Security Note
• https://git.kernel.org/stable/c/a20e16ebfe2fa65348eb4b2dc7deac330ce03e9c · Note
• https://git.kernel.org/stable/c/7169f326a23d0f547fcd90e68b72fd387622e126 · Note
• https://git.kernel.org/stable/c/d7a65a34d2453f8cd3e0cc0e1319740af7e24276 · Note
• https://git.kernel.org/stable/c/d55ffad8d422b5d1cc44dad32bd3d25f4471cd9f · Note
• https://git.kernel.org/stable/c/312ec973efac0efb9b9ed64214235910e9ecbaa8 · Note
• https://git.kernel.org/stable/c/301286c0ccd37d66b0e40786fd35a4f19cdbd88a · Note
• https://git.kernel.org/stable/c/28b0a2ab8c82d0bbdeb8013029c67c978ce6e4bf · Note
• https://git.kernel.org/stable/c/f2f95e6d4b97e70bb876139b0583fc8079983f85 · Note