<Issue Description> Spring Security OAuth versions 2.5.x prior to 2.5.2 and older unsupported versions are susceptible to a Denial-of-Service (DoS) attack via the initiation of the Authorization Request in an OAuth 2.0 Client 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. This vulnerability exposes OAuth 2.0 Client applications only.

Spring Security OAuth versions 2.3 prior to 2.3.6, 2.2 prior to 2.2.5, 2.1 prior to 2.1.5, and 2.0 prior to 2.0.18, as well as older unsupported versions could be susceptible to an open redirector attack that can leak an authorization code. A malicious user or attacker can craft a request to the authorization endpoint using the authorization code grant type, and specify a manipulated redirection URI via the redirect_uri parameter. This can cause the authorization server to redirect the resource owner user-agent to a URI under the control of the attacker with the leaked authorization code.

Spring Security OAuth, versions 2.3 prior to 2.3.5, and 2.2 prior to 2.2.4, and 2.1 prior to 2.1.4, and 2.0 prior to 2.0.17, and older unsupported versions could be susceptible to an open redirector attack that can leak an authorization code. A malicious user or attacker can craft a request to the authorization endpoint using the authorization code grant type, and specify a manipulated redirection URI via the "redirect_uri" parameter. This can cause the authorization server to redirect the resource owner user-agent to a URI under the control of the attacker with the leaked authorization code. This vulnerability exposes applications that meet all of the following requirements: Act in the role of an Authorization Server (e.g. @EnableAuthorizationServer) and uses the DefaultRedirectResolver in the AuthorizationEndpoint. This vulnerability does not expose applications that: Act in the role of an Authorization Server and uses a different RedirectResolver implementation other than DefaultRe…

Spring Security OAuth, versions 2.3 prior to 2.3.4, and 2.2 prior to 2.2.3, and 2.1 prior to 2.1.3, and 2.0 prior to 2.0.16, and older unsupported versions could be susceptible to a privilege escalation under certain conditions. A malicious user or attacker can craft a request to the approval endpoint that can modify the previously saved authorization request and lead to a privilege escalation on the subsequent approval. This scenario can happen if the application is configured to use a custom approval endpoint that declares AuthorizationRequest as a controller method argument. This vulnerability exposes applications that meet all of the following requirements: Act in the role of an Authorization Server (e.g. @EnableAuthorizationServer) and use a custom Approval Endpoint that declares AuthorizationRequest as a controller method argument. This vulnerability does not expose applications that: Act in the role of an Authorization Server and use the default Approval Endpoint, act in the ro…

Spring Security OAuth, versions 2.3 prior to 2.3.3, 2.2 prior to 2.2.2, 2.1 prior to 2.1.2, 2.0 prior to 2.0.15 and older unsupported versions contains a remote code execution vulnerability. A malicious user or attacker can craft an authorization request to the authorization endpoint that can lead to remote code execution when the resource owner is forwarded to the approval endpoint.

When processing authorization requests using the whitelabel views in Spring Security OAuth 2.0.0 to 2.0.9 and 1.0.0 to 1.0.5, the response_type parameter value was executed as Spring SpEL which enabled a malicious user to trigger remote code execution via the crafting of the value for response_type.