USN-7892-1: H2O vulnerability

Publication date

26 November 2025

Overview

H2O could be made to crash if it received specially crafted network traffic.


Packages

  • h2o - the optimized HTTP/1, HTTP/2 server

Details

It was discovered that H2O exhibited poor server resource management in its
HTTP/2 protocol. An attacker could possibly use this issue to cause H2O to
crash, resulting in a denial of service.

It was discovered that H2O exhibited poor server resource management in its
HTTP/2 protocol. An attacker could possibly use this issue to cause H2O 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
22.04 LTS jammy h2o –  2.2.5+dfsg2-6.1ubuntu2+esm1  
libh2o0.13 –  2.2.5+dfsg2-6.1ubuntu2+esm1  
20.04 LTS focal h2o –  2.2.5+dfsg2-3ubuntu0.1~esm1  
libh2o0.13 –  2.2.5+dfsg2-3ubuntu0.1~esm1  

Reduce your security exposure

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