Debian Security Advisory

DLA-2852-1 apache-log4j2 -- LTS security update

Date Reported:
26 Dec 2021
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 959450, Bug 1001891.
In Mitre's CVE dictionary: CVE-2020-9488, CVE-2021-45105.
More information:

Several security vulnerabilities were found in Apache Log4j2, a Logging Framework for Java, which could lead to a denial of service or information disclosure.

  • CVE-2020-9488

    Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through that appender.

  • CVE-2021-45105

    Apache Log4j2 did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted.

For Debian 9 stretch, these problems have been fixed in version 2.12.3-0+deb9u1.

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:

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