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 4.2.x up to 4.2.12, and older unsupported versions support plain text passwords using PlaintextPasswordEncoder. If an application using an affected version of Spring Security is leveraging PlaintextPasswordEncoder and a user has a null encoded password, a malicious user (or attacker) can authenticate using a password of "null".
The ActiveDirectoryLdapAuthenticator in Spring Security 3.2.0 to 3.2.1 and 3.1.0 to 3.1.5 does not check the password length. If the directory allows anonymous binds then it may incorrectly authenticate a user who supplies an empty password.