Using "" as a pattern in Spring Security configuration for WebFlux creates a mismatch in pattern matching between Spring Security and Spring WebFlux, and the potential for a security bypass.

A flaw was found in the spring-security framework. Spring Security could allow a remote attacker to bypass security restrictions caused by an issue when using forward or include dispatcher types. By sending a specially-crafted request, an attacker can bypass authorization rules.

A flaw was found in Spring Security. When using RegexRequestMatcher, an easy misconfiguration can bypass some servlet containers. Applications using RegexRequestMatcher with . in the regular expression are possibly vulnerable to an authorization bypass.