A varnish security update has been released for Debian GNU/Linux 9 LTS to address an issue that may lead to information disclosure and cache poisoning.

DLA 2920-1: varnish security update

-------------------------------------------------------------------------
Debian LTS Advisory DLA-2920-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Markus Koschany
February 14, 2022   https://wiki.debian.org/LTS
-------------------------------------------------------------------------

Package : varnish
Version : 5.0.0-7+deb9u3
CVE ID : CVE-2022-23959
Debian Bug : 1004433

James Kettle discovered that a request smuggling attack can be performed on
HTTP/1 connections on Varnish servers, high-performance web accelerators. The
smuggled request would be treated as an additional request by the Varnish
server which may lead to information disclosure and cache poisoning.

For Debian 9 stretch, this problem has been fixed in version
5.0.0-7+deb9u3.

We recommend that you upgrade your varnish packages.

For the detailed security status of varnish please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/varnish

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