Executive brief
Spring Security, a widely used framework for securing Java applications, contains a vulnerability in its SAML2 login and logout processing. An attacker could potentially use the system to help decrypt sensitive information by sending specially crafted, unsigned messages. While this does not directly grant access to the system, it could allow an attacker to slowly uncover encrypted data, potentially compromising user privacy or security tokens.
Technical details
A decryption oracle vulnerability exists in the Spring Security SAML2 Service Provider component. The root cause is that the library attempts to decrypt elements within SAML Responses, LogoutRequests, and LogoutResponses before verifying a valid cryptographic signature. A remote, unauthenticated attacker can craft malicious SAML payloads to observe the application's decryption behavior. This allows the attacker to use the Service Provider as a decryption oracle to potentially recover plaintext from encrypted SAML elements. The vulnerability is addressed in versions 6.5.11 and 7.0.6.
Affected products
- Spring Spring Security SAML2 Service Provider 5.7.0 - 5.7.23, 5.8.0 - 5.8.25, 6.3.0 - 6.3.16, 6.4.0 - 6.4.16, 6.5.0 - 6.5.10, 7.0.0 - 7.0.5
Timeline
- 2026-06-10: advisory
- 2026-06-10: disclosed
- 2026-08-12: patched