Bug 2520659 (CVE-2026-63495) - CVE-2026-63495 libevent: Libevent: Remote denial of service via unbounded memory accumulation in WebSocket server
Summary: CVE-2026-63495 libevent: Libevent: Remote denial of service via unbounded mem...
Keywords:
Status: NEW
Alias: CVE-2026-63495
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-20 18:05 UTC by OSIDB Bzimport
Modified: 2026-08-28 03:02 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-08-20 18:05:06 UTC 
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.
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