Published: 19 December 2021
Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) 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. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.
CVSS 3 base score: 5.9
Launchpad, Ubuntu, Debian
upstream: https://github.com/apache/logging-log4j2/commit/806023265f8c905b2dd1d81fd2458f64b2ea0b5e (2.x)
upstream: https://github.com/apache/logging-log4j2/commit/bf7e916df6335713fe2219c7b3b523fb509deabc (2.12.x)