Debian Security Advisory

DLA-3208-1 varnish -- LTS security update

Date Reported:
27 Nov 2022
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 956307, Bug 1023751.
In Mitre's CVE dictionary: CVE-2020-11653, CVE-2022-45060.
More information:

Martin van Kervel Smedshammer discovered a request forgery attack can be performed on Varnish Cache servers that have the HTTP/2 protocol turned on. An attacker may introduce characters through the HTTP/2 pseudo-headers that are invalid in the context of an HTTP/1 request line, causing the Varnish server to produce invalid HTTP/1 requests to the backend. This may in turn be used to successfully exploit vulnerabilities in a server behind the Varnish server.

For Debian 10 buster, these problems have been fixed in version 6.1.1-1+deb10u4.

We recommend that you upgrade your varnish packages.

For the detailed security status of varnish please refer to its security tracker page at:

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: