CVE-2026-80521: Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: af_unix: Unlink scc_entry in unix_del_edge(). Kyle Zeng reported that GC could free a dead SCC partially. The scenario is as follows: 1) Create two SCCs: X -. A <-> B ^--' 2) Run the following concurrently: 2-1) send() sk-B to sk-B from sk-X 2-2) close() both A and B At 2-1), there is a small window where unix_add_edges() publishes a new edge (B <-> B) to GC but its skb is not queued by skb_queue_tail(). If 2-2) completes before skb_queue_tail() and GC is triggered, it judges A <-> B as dead, but B is not freed because GC cannot collect the not-yet-queued skb holding the B <-> B edge. X -. A <-> B -. This edge is visible ^--' ^..' but skb is not This itself is not a problem since the next GC run will judge B as dead as well and free it finally. X -. A <.> B -. ^--' ^--' However, X's SCC forces the next GC to call unix_walk_scc_fast(), and it iterates over A through B's scc_entry. Let's unlink scc_entry before freeing the vertex in unix_del_edge().

Affected products

• Linux Linux: from 6.1.141, before 6.1.189 (fixed in 6.1.189); from 6.6.93, before 6.6.158 (fixed in 6.6.158); from 6.10, before 6.12.111 (fixed in 6.12.111); from 6.13, before 6.18.53 (fixed in 6.18.53); from 6.19, before 7.1.10 (fixed in 7.1.10)

Published 2026-08-26. Last modified 2026-10-03.