CVE-2025-11677

Use After Free in libwebsockets WebSocket server

MEDIUM
6.3
CVSS Score
Published: October 20, 2025 at 01:41 PM UTC
Updated: October 8, 2026 at 10:10 PM UTC
1 product affected across 1 vendorLibwebsockets

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Severity
MEDIUM6.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3 ≤ v ≤ 4.4.1,4.3.63

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.3MEDIUMNozomi
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-416

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