In spring security versions prior to 5.4.11+, 5.5.7+ , 5.6.4+ and older unsupported versions, RegexRequestMatcher can easily be misconfigured to be bypassed on some servlet containers. Applications using RegexRequestMatcher with `.` in the regular expression are possibly vulnerable to an authorization bypass.

Spring Security versions 5.5.x prior to 5.5.7, 5.6.x prior to 5.6.4, and earlier unsupported versions contain an integer overflow vulnerability. When using the BCrypt class with the maximum work factor (31), the encoder does not perform any salt rounds, due to an integer overflow error. The default settings are not affected by this CVE.

Spring Framework 3.0.0 through 3.0.5, Spring Security 3.0.0 through 3.0.5 and 2.0.0 through 2.0.6, and possibly other versions deserialize objects from untrusted sources, which allows remote attackers to bypass intended security restrictions and execute untrusted code by (1) serializing a java.lang.Proxy instance and using InvocationHandler, or (2) accessing internal AOP interfaces, as demonstrated using deserialization of a DefaultListableBeanFactory instance to execute arbitrary commands via the java.lang.Runtime class.