warmcat libwebsocket up to 4.3.6/4.4.2 lws_adns_parse_label stack-based overflow

Summaryinfo

A vulnerability classified as critical was found in warmcat libwebsocket up to 4.3.6/4.4.2. Affected is the function lws_adns_parse_label. Such manipulation leads to stack-based overflow. This vulnerability is uniquely identified as CVE-2025-11678. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, has been found in warmcat libwebsocket up to 4.3.6/4.4.2. Affected by this issue is the function lws_adns_parse_label. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS flag is enabled during compilation, to overflow the label_stack, when the attacker is able to sniff a DNS request in order to craft a response with a matching id containing a label longer than the maximum.

The weakness was disclosed by Raffaele Bova. The advisory is available at libwebsockets.org. This vulnerability is handled as CVE-2025-11678 since 10/13/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/27/2025).

The vulnerability scanner Nessus provides a plugin with the ID 271673 (Linux Distros Unpatched Vulnerability : CVE-2025-11678), 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 (271673) and EUVD (EUVD-2025-35057). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• warmcat

Name

• libwebsocket

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

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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