CVE-2026-63495 — Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames
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…
Published: 2026-08-20 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7