CVE-2026-89609

A MODERATE severity race condition flaw was found in the eCryptfs component of the Linux kernel. When an eCryptfs daemon terminates, ecryptfs_exorcise_daemon() drops the daemon's queued messages and moves those message contexts back to the free list without holding the ecryptfs_msg_ctx_lists_mux lock, which ecryptfs_msg_ctx_alloc_to_free() requires. A local low-privileged attacker able to trigger concurrent use of the global message context lists could race with this cleanup path, resulting in corruption of the shared list state and unpredictable system behavior or instability. Red Hat rated this flaw MODERATE (CVSS 7.0, CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) based on the local attack vector, the low privileges required, and the high attack complexity needed to reliably win the race; this differs from the upstream CVE.org score of 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), which assesses a lower attack complexity. The Red Hat Enterprise Linux kernel and kernel-rt streams evaluated for this flaw, as well as the OpenShift Container Platform 4 RHCOS components, are not affected because the vulnerable code is not present in those builds. OpenShift Container Platform 5.0 and 5.1 are affected, and the fix is currently deferred for those streams; the residual risk is that a local user on an affected node could trigger the race condition and cause system instability, although the local access requirement and high attack complexity limit practical exploitability.