CVE-2025-11679: Warmcat Libwebsockets

Medium severity, CVSS 5.9. EPSS: 0.4% chance of exploitation in the next 30 days.

Out-of-bounds Read in lws_upng_emit_next_line in warmcat libwebsockets allows, when the LWS_WITH_UPNG flag is enabled during compilation and the HTML display stack is used, to read past a heap allocated buffer possibly causing a crash, when the user visits an attacker controlled website that contains a crafted PNG file with a big height dimension.

Affected products

• Warmcat Libwebsockets: from 4.0, up to and including 4.4.2; from 4.0, up to and including 4.3.6

Published 2025-10-20. Last modified 2026-10-08.