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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History

Fri, 21 Aug 2026 13:30:00 +0000

Type Values Removed Values Added
First Time appeared Libevent Project
Libevent Project libevent
Vendors & Products Libevent Project
Libevent Project libevent

Thu, 20 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 20 Aug 2026 18:00:00 +0000

Type Values Removed Values Added
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.
Title Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames
Weaknesses CWE-400
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-20T19:17:04.616Z

Reserved: 2026-07-16T21:49:52.069Z

Link: CVE-2026-63495

cve-icon Vulnrichment

Updated: 2026-08-20T19:16:39.804Z

cve-icon NVD

Status : Received

Published: 2026-08-20T18:16:37.040

Modified: 2026-08-20T20:17:45.327

Link: CVE-2026-63495

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T13:01:16Z

Weaknesses