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Ubuntu Security Notice USN-5474-2
August 23, 2022

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

- Ubuntu 20.04 LTS

Summary:

Varnish Cache could be made to restart if it received specially crafted input.

Software Description:
- varnish: state of the art, high-performance web accelerator

Details:

USN-5474-1 fixed vulnerabilities in Varnish Cache. Unfortunately the fix for
CVE-2020-11653 was incomplete. This update fixes the problem.

Original advisory details:

 It was discovered that Varnish Cache could have an assertion failure when a
 TLS termination proxy uses PROXY version 2. A remote attacker could possibly
 use this issue to restart the daemon and cause a performance loss.
 (CVE-2020-11653)

Update instructions:

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

Ubuntu 20.04 LTS:
  libvarnishapi2                  6.2.1-2ubuntu0.2
  varnish                         6.2.1-2ubuntu0.2

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

References:
  https://ubuntu.com/security/notices/USN-5474-2
  https://ubuntu.com/security/notices/USN-5474-1
  CVE-2020-11653

Package Information:
  https://launchpad.net/ubuntu/+source/varnish/6.2.1-2ubuntu0.2