CVE-2025-11677

unknown

Published — · Modified —

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CVSS v3

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CVSS v4 NEW

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not yet in upstream

VIR risk

—

Description

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.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Debian Security Tracker · View original ↗ · DFSG

CVE-2025-11677 NameCVE-2025-11677 DescriptionUse 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. SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat,…

CVE-2025-11677

Name	CVE-2025-11677
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4373-1
Debian Bugs	1118747

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libwebsockets (PTS)	bullseye	4.0.20-2	vulnerable
	bullseye (security)	4.0.20-2+deb11u1	fixed
	bookworm	4.1.6-3	vulnerable
	trixie	4.3.5-1+deb13u1	fixed
	forky	4.3.5-4.1	fixed
	sid	4.3.5-5	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin	Debian Bugs
libwebsockets	source	bullseye	4.0.20-2+deb11u1	DLA-4373-1
libwebsockets	source	trixie	4.3.5-1+deb13u1
libwebsockets	source	(unstable)	4.3.5-3		1118747

Notes

[bookworm] - libwebsockets <no-dsa> (Minor issue)
https://libwebsockets.org/git/libwebsockets/commit?id=2f082ec31261f556969160143ba94875d783971a

Home - Debian Security - Source (Git)

Apply commands

text fix

Notes

[bookworm] - libwebsockets <no-dsa> (Minor issue)https://libwebsockets.org/git/libwebsockets/commit?id=2f082ec31261f556969160143ba94875d783971a

OS impact

Debian Mixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`4.3.5-1+deb13u1`
sid	Fixed	`4.3.5-3`
forky	Fixed	`4.3.5-3`
bullseye	Fixed	`4.0.20-2+deb11u1`
bookworm	Affected	—

References

https://security-tracker.debian.org/tracker/CVE-2025-11677

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.