Use After Free Affecting libwebsockets package, versions <4.3.5-1+deb13u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.41% (35th percentile)

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  • Snyk IDSNYK-ECHOLATEST-LIBWEBSOCKETS-19256847
  • published25 Aug 2026
  • disclosed20 Oct 2025

Introduced: 20 Oct 2025

CVE-2025-11677  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Echo:latest libwebsockets to version 4.3.5-1+deb13u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libwebsockets package and not the libwebsockets package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

Use After Free in WebSocket server implementation in lws_handshake_server in warmcat libwebsockets may allow an attacker, in specific configurations where the user provides a callback function that handles LWS_CALLBACK_HTTP_CONFIRM_UPGRADE, to achieve denial of service.

CVSS Base Scores

version 3.1