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USN-5474-2: Varnish Cache regression

23 August 2022

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



  • varnish - state of the art, high-performance web accelerator


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.

Update instructions

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

Ubuntu 20.04

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


Related notices

  • USN-5474-1: libvarnishapi1, varnish, libvarnishapi2, varnish-doc, libvarnishapi-dev