Use After Free The advisory has been revoked - it doesn't affect any version of package rtla  (opens in a new tab)


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  • Snyk IDSNYK-CENTOS10-RTLA-19798653
  • published15 Sept 2026
  • disclosed11 Sept 2026

Introduced: 11 Sep 2026

CVE-2026-89654  (opens in a new tab)
CWE-416  (opens in a new tab)

Amendment

The Centos security team deemed this advisory irrelevant for Centos:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rtla package and not the rtla package as distributed by Centos.

In the Linux kernel, the following vulnerability has been resolved:

ceph: fix UAF in check_new_map() on session freed during unlock

check_new_map() iterates mdsc->sessions[] and for each active session drops mdsc->mutex to perform per-session operations. The forced-close path (rank removed from map) correctly takes a reference on s via ceph_get_mds_session() before releasing mdsc->mutex, but three other paths do not:

Path A (address changed): mutex_unlock → mutex_lock(&s->s_mutex) Path B (reconnect): mutex_unlock → send_mds_reconnect(mdsc, s) Path C (active transition): mutex_unlock → mutex_lock(&s->s_mutex)

Without the extra reference, another thread can acquire mdsc->mutex during the unlock window, call __unregister_session() which drops the last reference on s, and free it. The original thread then accesses freed memory via s->s_mutex.

Fix by adding ceph_get_mds_session(s) before each mutex_unlock and ceph_put_mds_session(s) after the corresponding mutex_lock, matching the pattern already used in the forced-close path.

Race timeline (Path A):

Thread A (check_new_map) Thread B (another map update holds mdsc->mutex or session teardown)


s = mdsc->sessions[i] (refcount == 1, held only by sessions[] array)

mutex_unlock(&mdsc->mutex) ---> acquires mdsc->mutex __unregister_session(mdsc, s) sessions[i] = NULL ceph_put_mds_session(s) refcount: 1 -> 0 kfree(s) <--- freed!

mutex_lock(&s->s_mutex) UAF on freed s->s_mutex