Home / mailings [USN-8956-2] Brotli vulnerability
Posted on 30 October 2026
Ubuntu Security==========================================================================Ubuntu Security Notice USN-8956-2
October 27, 2026
brotli vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
Brotli could be made to crash or run programs if it received specially
crafted input.
Software Description:
- brotli: lossless compression algorithm and format (command line utility)
Details:
USN-8956-1 fixed a vulnerability in Brotli. This update provides the
corresponding fixes for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and
Ubuntu 20.04 LTS.
Original advisory details:
It was discovered that Brotli incorrectly handled certain compressed
streams. A remote attacker could possibly use this issue to cause a
denial of service or execute arbitrary code.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 20.04 LTS
brotli 1.0.7-6ubuntu0.1+esm1
Available with Ubuntu Pro
libbrotli1 1.0.7-6ubuntu0.1+esm1
Available with Ubuntu Pro
python3-brotli 1.0.7-6ubuntu0.1+esm1
Available with Ubuntu Pro
Ubuntu 18.04 LTS
brotli 1.0.3-1ubuntu1.3+esm1
Available with Ubuntu Pro
libbrotli1 1.0.3-1ubuntu1.3+esm1
Available with Ubuntu Pro
python-brotli 1.0.3-1ubuntu1.3+esm1
Available with Ubuntu Pro
python3-brotli 1.0.3-1ubuntu1.3+esm1
Available with Ubuntu Pro
Ubuntu 16.04 LTS
brotli 1.0.3-1ubuntu1~16.04.2+esm1
Available with Ubuntu Pro
libbrotli1 1.0.3-1ubuntu1~16.04.2+esm1
Available with Ubuntu Pro
python-brotli 1.0.3-1ubuntu1~16.04.2+esm1
Available with Ubuntu Pro
python3-brotli 1.0.3-1ubuntu1~16.04.2+esm1
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8956-2
https://ubuntu.com/security/notices/USN-8956-1
CVE-2026-111497
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