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CVE-2026-89990: Linux

Severity

9.8 (CRITICAL)

Vendor

LINUX

Affected versions

596afb0b8933ba6ed7227adcc538db26feb25c74 through before 729c1ff670ece6f3d4b1738365a0b2f90d487523; 596afb0b8933ba6ed7227a

Patch status

Patched

Published

2026-09-16T11:17:10.133

Modified

2026-09-16T15:18:22.800

Why it matters

Critical vulnerability requiring immediate validation against your environment.

Recommended admin actions

• Prioritize validation immediately due to critical CVSS severity.

Technical summary

In the Linux kernel, the following vulnerability has been resolved: ceph: lock mutex in ceph_mds_check_access() MDS session OPEN handling replaces mdsc->s_cap_auths under mdsc->mutex, freeing the previous array and its strings. ceph_mds_check_access() traverses this array without holding the mutex. A concurrent session reopen can therefore free the array while it is being inspected, resulting in a use-after-free like this: Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9 […] Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE [..] pc : ceph_mds_check_access+0xd4/0x550 lr : ceph_mds_check_access+0xc8/0x550 […] Call trace: ceph_mds_check_access+0xd4/0x550 (P) ceph_atomic_open+0x138/0xbe8 path_openat+0xa24/0xfa8 do_filp_open+0x94/0x158 do_sys_openat2+0x88/0xf8

View the official NVD record for CVE-2026-89990

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.