Quick answers
- Is CVE-2026-63380 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-63380 being exploited in the wild.
- How severe is CVE-2026-63380?
- Informational severity, with a CVSS score of 0, published 20 August 2026.
- Which products and versions are affected?
- Libevent prior to 2.2.2-alpha.
- Is there a fix for CVE-2026-63380?
- A patch was published on 2026-07-01: Fixed in version 2.2.2-alpha Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-63380 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-63380?
- Check whether you run Libevent at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is a null pointer dereference in the error path of the evws_new_session() function in ws.c. The root cause is a logic error where evws_connection_free() calls TAILQ_REMOVE on a websocket session that was never inserted into the http_server->ws_sessions list, because the failure occurred after evhttp_start_ws_() succeeded but before bufferevent_enable_locking_() completed. This causes the function to dereference invalid list pointers and trigger a segmentation fault. The attack requires local access and the ability to induce specific memory allocation or locking failures. The issue is fixed in version 2.2.2-alpha and later.
Affected products
- Libevent Libevent prior to 2.2.2-alpha
Timeline
- 2026-08-20: disclosed
- 2026-07-01: patched: Fixed in version 2.2.2-alpha