A flaw was found in the redirect_uri validation logic in Keycloak. This issue may allow a bypass of otherwise explicitly allowed hosts. A successful attack may lead to an access token being stolen, making it possible for the attacker to impersonate other users.

Keycloak's device authorization grant does not correctly validate the device code and client ID. An attacker client could abuse the missing validation to spoof a client consent request and trick an authorization admin into granting consent to a malicious OAuth client or possible unauthorized access to an existing OAuth client.

A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is appended to the token. This issue could allow an attacker to submit a specially crafted request leading to cross-site scripting (XSS) or further attacks. This flaw is the result of an incomplete fix for CVE-2020-10748.

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.

A flaw was found in undertow. Servlets annotated with @MultipartConfig may cause an OutOfMemoryError due to large multipart content. This may allow unauthorized users to cause remote Denial of Service (DoS) attack. If the server uses fileSizeThreshold to limit the file size, it's possible to bypass the limit by setting the file name in the request to null.

A flaw was found in Red Hat Single Sign-On for OpenShift container images, which are configured with an unsecured management interface enabled. This flaw allows an attacker to use this interface to deploy malicious code and access and modify potentially sensitive information in the app server configuration.

A flaw was found in the offline_access scope in Keycloak. This issue would affect users of shared computers more (especially if cookies are not cleared), due to a lack of root session validation, and the reuse of session ids across root and user authentication sessions. This enables an attacker to resolve a user session attached to a previously authenticated user; when utilizing the refresh token, they will be issued a token for the original user.

A flaw was found in undertow. This issue makes achieving a denial of service possible due to an unexpected handshake status updated in SslConduit, where the loop never terminates.

Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the SAML or OIDC providers. The vulnerability can allow an attacker to execute malicious scripts by setting the AssertionConsumerServiceURL value or the redirect_uri.