Ubuntu Security Notices USN-8233-1 USN-8233-1: nghttp2 vulnerability Publication date 5 May 2026 Overview nghttp2 could be made to crash if it received specially crafted network traffic. Releases 25.10 24.04 LTS 22.04 LTS 20.04 LTS 18.04 LTS 16.04 Open side navigation Close side navigation Packages Details Update instructions References Packages nghttp2 - HTTP/2 C Library and tools Details Andrew MacPherson discovered that nghttp2 did not properly validate internal state when the session termination API was called. A remote attacker could possibly use this issue to cause nghttp2 to crash, resulting in a denial of service. Andrew MacPherson discovered that nghttp2 did not properly validate internal state when the session termination API was called. A remote attacker could possibly use this issue to cause nghttp2 to crash, resulting in a denial of service. 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 25.10 questing libnghttp2-14 – 1.64.0-1.1ubuntu1.1 nghttp2 – 1.64.0-1.1ubuntu1.1 24.04 LTS noble libnghttp2-14 – 1.59.0-1ubuntu0.3 nghttp2 – 1.59.0-1ubuntu0.3 22.04 LTS jammy libnghttp2-14 – 1.43.0-1ubuntu0.3 nghttp2 – 1.43.0-1ubuntu0.3 20.04 LTS focal libnghttp2-14 – 1.40.0-1ubuntu0.3+esm1 Ubuntu Pro Fix available with Ubuntu Pro . nghttp2 – 1.40.0-1ubuntu0.3+esm1 Ubuntu Pro Fix available with Ubuntu Pro . 18.04 LTS bionic libnghttp2-14 – 1.30.0-1ubuntu1+esm3 Ubuntu Pro Fix available with Ubuntu Pro . nghttp2 – 1.30.0-1ubuntu1+esm3 Ubuntu Pro Fix available with Ubuntu Pro . 16.04 xenial libnghttp2-14 – 1.7.1-1ubuntu0.1~esm3 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. nghttp2 – 1.7.1-1ubuntu0.1~esm3 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. Get Ubuntu Pro References CVE-2026-27135 CVE-2026-27135