<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.

A reflected cross-site scripting (XSS) vulnerability in the Symantec Layer7 API Management OAuth Toolkit (OTK) allows a remote attacker to craft a malicious URL for the OTK web UI and target OTK users with phishing attacks or other social engineering techniques. A successful attack allows injecting malicious code into the OTK web UI client application.

lib/oauth/consumer.rb in the oauth-ruby gem through 0.5.4 for Ruby does not verify server X.509 certificates if a certificate bundle cannot be found, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information.

PKCE support is not implemented in accordance with the RFC for OAuth 2.0 for Native Apps. Without the use of PKCE, the authorization code returned by an authorization server is not enough to guarantee that the client that issued the initial authorization request is the one that will be authorized. An attacker is able to obtain the authorization code using a malicious app on the client-side and use it to gain authorization to the protected resource. This affects the package com.google.oauth-client:google-oauth-client before 1.31.0.

Jenkins Bitbucket OAuth Plugin 0.9 and earlier stored credentials unencrypted in the global config.xml configuration file on the Jenkins master where they could be viewed by users with access to the master file system.

An arbitrary file read vulnerability in Jenkins Google OAuth Credentials Plugin 0.9 and earlier allowed attackers able to configure jobs and credentials in Jenkins to obtain the contents of any file on the Jenkins master.

The oauth2-provider plugin before 3.1.5 for WordPress has incorrect generation of random numbers.

A session fixation vulnerability in Jenkins Gitlab Authentication Plugin 1.4 and earlier in GitLabSecurityRealm.java allows unauthorized attackers to impersonate another user if they can control the pre-authentication session.

An open redirect vulnerability in Jenkins Gitlab Authentication Plugin 1.4 and earlier in GitLabSecurityRealm.java allows attackers to redirect users to a URL outside Jenkins after successful login.

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.