CVE-2026-63380 Libevent: Null Pointer Dereference in `evws_new_session`
A local attacker can crash the application by triggering a null pointer dereference in Libevent's WebSocket session handling during error paths.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-63380?
CVE-2026-63380 is a medium-severity vulnerability in libevent, published on 20 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.
Which versions are affected by CVE-2026-63380?
How do I fix CVE-2026-63380?
No fix has been published for CVE-2026-63380 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-63380 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63380 exists.
Sources
Also known as AZL-96912, GHSA-3rpf-frgx-xq34, UBUNTU-CVE-2026-63380.