USN-8954-1: zlib vulnerability

Publication date

22 October 2026

Overview

zlib could be made to crash or run programs if it received specially crafted input.


Packages

  • zlib - Lossless data-compression library

Details

Ali Firas discovered that zlib incorrectly handled certain non-blocking
write operations. An attacker could possibly use this issue to trigger a
heap buffer overflow, resulting in a denial of service or arbitrary code
execution.

Ali Firas discovered that zlib incorrectly handled certain non-blocking
write operations. An attacker could possibly use this issue to trigger a
heap buffer overflow, resulting in a denial of service or arbitrary code
execution.

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:


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.


Have additional questions?

Talk to a member of the team ›