EUVD-2026-35911

SubjectDnX509PrincipalExtractor does not correctly handle certain malformed X.509 certificate CN values, which can lead to reading the wrong value for the username. In a carefully crafted certificate, this can lead to an attacker impersonating another user. Affected versions: Spring Security 5.7....

Certificate Impersonation

spring-security-web is vulnerable to certificate impersonation. The vulnerability is due to improper parsing of malformed X.509 certificate CN values in SubjectX500PrincipalExtractor, which can result in extracting an incorrect username and allow attackers to impersonate another user...