Debian 11: DSA-5024-1 Critical: Apache Log4j2 DoS Threat

It was found that Apache Log4j2, a Logging Framework for Java, did not protect
from uncontrolled recursion from self-referential lookups. When the logging
configuration uses a non-default Pattern Layout with a Context Lookup (for
example, $${ctx:loginId}), attackers with control over Thread Context Map (MDC)
input data can craft malicious input data that contains a recursive lookup,
resulting in a denial of service.

For the oldstable distribution (buster), this problem has been fixed
in version 2.17.0-1~deb10u1.

For the stable distribution (bullseye), this problem has been fixed in
version 2.17.0-1~deb11u1.

We recommend that you upgrade your apache-log4j2 packages.

For the detailed security status of apache-log4j2 please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/apache-log4j2

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/sec...