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.

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 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.

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.

A flaw was found in Keycloak in the execute-actions-email endpoint. This issue allows arbitrary HTML to be injected into emails sent to Keycloak users and can be misused to perform phishing or other attacks against users.