The flaw is a race condition between the garbage‑collection (GC) process and the MSG_PEEK call in the Linux kernel's Unix domain socket code. When MSG_PEEK is performed on a socket whose peer is later closed, the reference counter for the socket’s file is silently increased. The GC thread, running concurrently, misinterprets this state change and decides that both sockets are dead, purging the receive queue of a socket that is still in use. The result is that data lost by the affected application cannot be retrieved, effectively breaking reliable communication and potentially causing a denial of service. The underlying weakness is a concurrency bug (CWE‑367).

All systems running the Linux kernel before the inclusion of the upstream fix for the MSG_PEEK/GC race are vulnerable. The advisory does not list specific distribution names or precise kernel versions, so affected users should verify that their kernel revision predates the commit that corrects the issue. The pressure is on any kernel that still relies on the older garbage‑collection algorithm for Unix sockets.

The CVSS score of 5.5 indicates moderate severity, and the EPSS score of less than 1 % coupled with the absence from KEV suggests a relatively low likelihood of exploitation. The race condition requires the attacker to be able to execute a MSG_PEEK on a Unix domain socket that shares a socket reference with another socket that is subsequently closed, implying a local execution context. The vulnerability does not provide remote code execution or direct system compromise; the impact is limited to loss of queued data and potential service disruption. The inferred attack vector is local user or process with access to the vulnerable Unix socket; this inference is based on the need for concurrent access to both sockets and is not explicitly stated in the description.