CVE-2025-11680

Out-of-bounds Write in libwebsockets PNG parsing

State: Published
Severity: 5.9 Medium
Published: Oct 20, 2025
Updated: Oct 20, 2025
Reserved: Oct 13, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	5.9 Medium	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	Nozomi

Weaknesses

CWE-787 Out-of-bounds Write

Affected Products

Product	Versions
libwebsocketswarmcat	4.0 through 4.4.2Affected 4.0 through 4.3.6Affected

References

https://libwebsockets.org/git/libwebsockets/commit?id=2b715249f39291c86443b969a1088d59b6a89b78patchvendor-advisory
https://www.nozominetworks.com/labs/vulnerability-advisories-cve-2025-11680third-party-advisory

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