It was discovered that there was two issues in shiro, a security framework for Java application:

• CVE-2020-1957

  Apache Shiro before 1.5.2, when using Apache Shiro with Spring dynamic controllers, a specially crafted request may cause an authentication bypass.

• CVE-2020-11989

  Apache Shiro before 1.5.3, when using Apache Shiro with Spring dynamic controllers, a specially crafted request may cause an authentication bypass.

For Debian 9 Stretch, these problems have been fixed in version 1.3.2-1+deb9u1.

We recommend that you upgrade your shiro packages.

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