Vulnerability Description
Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a total message-size limit. An unauthenticated remote client can repeatedly send fragmented WebSocket frames below WS_MAX_RECV_FRAME_SZ with FIN=0, causing the evbuffer to grow without bound until the process or host exhausts memory. This issue is fixed in version 2.2.2-alpha.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/libevent/libevent/commit/291c4d1cd75695e898030ebd5c4ddf26c094
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
- https://github.com/libevent/libevent/security/advisories/GHSA-qx89-wf2v-vgmx
- https://github.com/libevent/libevent/security/advisories/GHSA-qx89-wf2v-vgmx
FAQ
What is CVE-2026-63495?
CVE-2026-63495 is a vulnerability with a CVSS score of 7.5 (HIGH). Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a to...
How severe is CVE-2026-63495?
CVE-2026-63495 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-63495?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.