A HAProxy security update has been released for Ubuntu Linux 20.04 LTS and 21.04.

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Ubuntu Security Notice USN-5063-1
September 08, 2021

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

- Ubuntu 21.04
- Ubuntu 20.04 LTS

Summary:

HAProxy could be made to expose sensitive information over the network.

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

Details:

Ori Hollander discovered that HAProxy incorrectly handled HTTP header name
length encoding. A remote attacker could possibly use this issue to inject
a duplicate content-length header and perform request smuggling attacks.

Update instructions:

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

Ubuntu 21.04:
haproxy 2.2.9-1ubuntu0.2

Ubuntu 20.04 LTS:
haproxy 2.0.13-2ubuntu0.3

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

References:
  https://ubuntu.com/security/notices/USN-5063-1
CVE-2021-40346

Package Information:
  https://launchpad.net/ubuntu/+source/haproxy/2.2.9-1ubuntu0.2
  https://launchpad.net/ubuntu/+source/haproxy/2.0.13-2ubuntu0.3