A Polymorphic Typing issue was discovered in FasterXML jackson-databind 2.x before 2.9.9.2. This occurs when Default Typing is enabled (either globally or for a specific property) for an externally exposed JSON endpoint and the service has the logback jar in the classpath.
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
https://www.oracle.com/security-alerts/cpujul2020.html
https://www.oracle.com/security-alerts/cpujan2020.html
https://www.oracle.com/security-alerts/cpuapr2020.html
https://www.debian.org/security/2019/dsa-4542
https://security.netapp.com/advisory/ntap-20190814-0001/
https://seclists.org/bugtraq/2019/Oct/6
https://lists.debian.org/debian-lts-announce/2019/08/msg00011.html
https://github.com/FasterXML/jackson-databind/issues/2389
https://github.com/FasterXML/jackson-databind/commit/ad418eeb974e357f2797aef64aa0e3ffaaa6125b