SB20260912131 - Out-of-bounds write in Linux kernel ceph

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-89656)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to write beyond the CRUSH workspace.

The vulnerability exists due to improper validation of bucket IDs in the libceph CRUSH map decoder, crush_decode(), when processing a malformed CRUSH map containing a bucket ID that does not match its array slot. A local user can cause the kernel to process such a map and write past a permutation array into memory beyond the CRUSH workspace.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/00562ccd4e88d092b9b851df50fad20442bfeb24
• https://git.kernel.org/stable/c/3516a4131c4e45d62ee4e42e82c36930e8c1fbbd
• https://git.kernel.org/stable/c/3cde4a8302301679937474a5f7a851394cc1bd11
• https://git.kernel.org/stable/c/79900d978158b2d80eef952fc41b9e4dc58d7b83