CVE-2026-63495

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/libevent/libevent/commit/291c4d1cd75695e898030ebd5c4ddf26c094077b
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

Configurations

No configuration.

History

26 Oct 2026, 10:10

Type	Values Removed	Values Added
Summary		(es) Libevent es una biblioteca de notificación de eventos. Desde 2.2.0-alpha-dev hasta 2.2.2-alpha, el servidor WebSocket de libevent en ws.c acumula tramas fragmentadas en evws -> incomplete_frames sin aplicar un límite de tamaño total de mensaje. Un cliente remoto no autenticado puede enviar repetidamente tramas WebSocket fragmentadas por debajo de WS_MAX_RECV_FRAME_SZ con FIN=0, haciendo que el evbuffer crezca sin límite hasta que el proceso o el host agote la memoria. Este problema está solucionado en la versión 2.2.2-alpha.

Information

Published : 2026-08-20 18:16

Updated : 2026-10-26 10:10

NVD link : CVE-2026-63495

Mitre link : CVE-2026-63495

CVE.ORG link : CVE-2026-63495

JSON object : View

Products Affected

No product.

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-770

Allocation of Resources Without Limits or Throttling

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