USN-8024-1: Libwebsockets vulnerabilities

Publication date

11 February 2026

Overview

Several security issues were fixed in Libwebsockets.


Packages

  • libwebsockets - C library for building WebSocket-based network applications

Details

Raffaele Bova discovered that Libwebsockets incorrectly handled memory
when the upgrade header is not valid in the WebSocket server. An
attacker could possibly use this issue to cause a denial of service.
(CVE-2025-11677)

Raffaele Bova discovered that Libwebsockets did not properly check the
size of the destination buffer in the async-dns component. An attacker
could possibly use this issue to cause applications to crash, leading to a
denial of service, or possibly execute arbitrary code. This issue only
affected Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2025-11678)

Raffaele Bova discovered that Libwebsockets incorrectly handled memory
when the upgrade header is not valid in the WebSocket server. An
attacker could possibly use this issue to cause a denial of service.
(CVE-2025-11677)

Raffaele Bova discovered that Libwebsockets did not properly check the
size of the destination buffer in the async-dns component. An attacker
could possibly use this issue to cause applications to crash, leading to a
denial of service, or possibly execute arbitrary code. This issue only
affected Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2025-11678)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
24.04 LTS noble libwebsockets19t64 –  4.3.3-1.1ubuntu0.1~esm1  
22.04 LTS jammy libwebsockets16 –  4.0.20-2ubuntu1.1
20.04 LTS focal libwebsockets15 –  3.2.1-3ubuntu0.1~esm1  

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