Use-after-free in Linux kernel - CVE-2026-80521

Vulnerability details

The vulnerability allows a local user to execute arbitrary code or cause a denial of service.

The vulnerability exists due to a use-after-free in unix_del_edge() and the af_unix garbage collector when processing concurrent socket edge updates and garbage collection. A local user can trigger concurrent send() and close() operations on crafted unix socket reference cycles to execute arbitrary code or cause a denial of service.

The issue occurs in a race window where a new edge becomes visible to garbage collection before its skb is queued, allowing a dead strongly connected component to be partially freed while stale scc_entry state remains reachable during a later GC walk.

Affected software

How to mitigate CVE-2026-80521

External References

• https://git.kernel.org/stable/c/594d905195024b228c962627ae5ae7c17bd582a4
• https://git.kernel.org/stable/c/e3702470ced94fad74d71e2232f022d2eb752a6d

Related Security Bulletins

• Use-after-free in Linux kernel unix