warmcat libwebsockets up to 4.3.6/4.4.2 PNG File Parser unfilter_scanline width out-of-bounds write

Summaryinfo

A vulnerability was found in warmcat libwebsockets up to 4.3.6/4.4.2. It has been declared as critical. Impacted is the function unfilter_scanline of the component PNG File Parser. Such manipulation of the argument width leads to out-of-bounds write. This vulnerability is listed as CVE-2025-11680. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in warmcat libwebsockets up to 4.3.6/4.4.2. It has been rated as critical. Affected by this issue is the function unfilter_scanline of the component PNG File Parser. The manipulation of the argument width with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was presented by Raffaele Bova. The advisory is shared for download at libwebsockets.org. This vulnerability is handled as CVE-2025-11680 since 10/13/2025. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/28/2025).

The vulnerability scanner Nessus provides a plugin with the ID 271663 (Linux Distros Unpatched Vulnerability : CVE-2025-11680), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (271663) and EUVD (EUVD-2025-35055). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• warmcat

Name

• libwebsockets

Version

• 4.3.0
• 4.3.1
• 4.3.2
• 4.3.3
• 4.3.4
• 4.3.5
• 4.3.6
• 4.4.0
• 4.4.1
• 4.4.2

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion