[USN-8459-1] HAProxy vulnerabilities

[noreply+usn-bot at canonical.com]

==========================================================================
Ubuntu Security Notice USN-8459-1
June 22, 2026

haproxy vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 26.04 LTS
- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in HAProxy.

Software Description:
- haproxy: fast and reliable load balancing reverse proxy

Details:

It was discovered that HAProxy incorrectly handled the FCGI demultiplexer
record length field. A remote attacker could possibly use this issue to
cause incorrect request routing, response smuggling, or other memory safety
issues. (CVE-2026-55203)

It was discovered that HAProxy failed to validate the return value of the
HPACK dynamic table defragmentation function when memory was exhausted. A
remote attacker could possibly use this issue to cause HAProxy to crash,
resulting in a denial of service. (CVE-2026-55204)

Update instructions:

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

Ubuntu 26.04 LTS
  haproxy                         3.2.9-1ubuntu2.2

Ubuntu 25.10
  haproxy                         3.0.12-0ubuntu0.25.10.5

Ubuntu 24.04 LTS
  haproxy                         2.8.16-0ubuntu0.24.04.3

Ubuntu 22.04 LTS
  haproxy                         2.4.30-0ubuntu0.22.04.2

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

References:
  https://ubuntu.com/security/notices/USN-8459-1
  CVE-2026-55203, CVE-2026-55204

Package Information:
  https://launchpad.net/ubuntu/+source/haproxy/3.2.9-1ubuntu2.2
  https://launchpad.net/ubuntu/+source/haproxy/3.0.12-0ubuntu0.25.10.5
  https://launchpad.net/ubuntu/+source/haproxy/2.8.16-0ubuntu0.24.04.3
  https://launchpad.net/ubuntu/+source/haproxy/2.4.30-0ubuntu0.22.04.2
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