An apache2 security update has been released for Debian GNU/Linux 10 and 11 to address several vulnerabilities.

DSA 4982-1: apache2 security update

- -------------------------------------------------------------------------
Debian Security Advisory DSA-4982-1 security@debian.org
  https://www.debian.org/security/ Moritz Muehlenhoff
October 08, 2021   https://www.debian.org/security/faq
- -------------------------------------------------------------------------

Package : apache2
CVE ID : CVE-2021-34798 CVE-2021-36160 CVE-2021-39275 CVE-2021-40438

Several vulnerabilities have been found in the Apache HTTP server, which
could result in denial of service. In addition a vulnerability was
discovered in mod_proxy with which an attacker could trick the server
to forward requests to arbitrary origin servers.

For the oldstable distribution (buster), these problems have been fixed
in version 2.4.38-3+deb10u6.

For the stable distribution (bullseye), these problems have been fixed in
version 2.4.51-1~deb11u1.

We recommend that you upgrade your apache2 packages.

For the detailed security status of apache2 please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/apache2

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