CVE-2023-54226: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54226 is a data race vulnerability in the Linux kernel's AF_UNIX socket implementation, specifically in the handling of the sk->sk_shutdown field. The flaw was identified by KCSAN (Kernel Concurrency Sanitizer) and involves concurrent, unsynchronized access to sk->sk_shutdown between unix_release_sock()/unix_shutdown() (which write under unix_state_lock()) and unix_poll()/unix_dgram_poll() (which read it locklessly). It affects the Linux kernel and was published on December 30, 2025. The CVSS category is estimated as Medium, with an EPSS score of 0.024% (Feedly).

The root cause is a data race (CWE-362: Concurrent Execution Using Shared Resource with Improper Synchronization) in net/unix/af_unix.c. The sk->sk_shutdown field is written by unix_release_sock() (at line 631) and unix_shutdown() under unix_state_lock(), but read without any lock or atomic annotation by unix_poll() and unix_dgram_poll(). The fix annotates the writes with WRITE_ONCE() and reads with READ_ONCE() to prevent compiler and CPU reordering that could cause inconsistent state observations. Exploitation requires local access and the ability to trigger concurrent socket operations (Feedly).

The data race can lead to undefined behavior in the kernel's Unix domain socket polling logic, potentially causing incorrect poll results, kernel instability, or in edge cases, information disclosure due to stale or torn reads of the shutdown state. The primary availability impact is the risk of kernel crashes or hangs under concurrent socket workloads. Confidentiality and integrity impacts are limited, as the race affects internal socket state visibility rather than direct data exposure (Feedly).

The fix has been applied to the Linux kernel stable trees via multiple commits (e.g., 1c488f4e95b4, 8307e372e744, 196528ad4844, a41559ae3681, e1d09c2c2f57). Users should update to a patched kernel version that includes these commits. Linux distributions including Amazon Linux 2 have issued advisories (e.g., ALAS2-2026-3165) incorporating the fix. No configuration-based workaround is available; upgrading the kernel is the recommended remediation (Feedly, Amazon ALAS).