CVE-2025-11680: Warmcat Libwebsockets

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

Out-of-bounds Write in unfilter_scanline in warmcat libwebsockets allows, when the LWS_WITH_UPNG flag is enabled during compilation and the HTML display stack is used, to write 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 width value that causes an integer overflow which value is used for determining the size of a heap allocation.

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.