Spring Security versions 5.5.x prior to 5.5.1, 5.4.x prior to 5.4.7, 5.3.x prior to 5.3.10 and 5.2.x prior to 5.2.11 are susceptible to a Denial-of-Service (DoS) attack via the initiation of the Authorization Request in an OAuth 2.0 Client Web and WebFlux application. A malicious user or attacker can send multiple requests initiating the Authorization Request for the Authorization Code Grant, which has the potential of exhausting system resources using a single session or multiple sessions.

A flaw was found in Spring Framework. The encoder does not perform any salt rounds when using the BCrypt class with the maximum work factor (31) due to an integer overflow error.