The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

A flaw was found in npm-serialize-javascript. The vulnerability occurs because the serialize-javascript module does not properly sanitize certain inputs, such as regex or other JavaScript object types, allowing an attacker to inject malicious code. This code could be executed when deserialized by a web browser, causing Cross-site scripting (XSS) attacks. This issue is critical in environments where serialized data is sent to web clients, potentially compromising the security of the website or web application using this package.

A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming requests. This issue could allow an attacker to construct a cookie value to exfiltrate HttpOnly cookie values or spoof arbitrary additional cookie values, leading to unauthorized data access or modification. The main threat from this flaw impacts data confidentiality and integrity.

A flaw was found in the SAML client registration in Keycloak that could allow an administrator to register malicious JavaScript URIs as Assertion Consumer Service POST Binding URLs (ACS), posing a Cross-Site Scripting (XSS) risk. This issue may allow a malicious admin in one realm or a client with registration access to target users in different realms or applications, executing arbitrary JavaScript in their contexts upon form submission. This can enable unauthorized access and harmful actions, compromising the confidentiality, integrity, and availability of the complete KC instance.

A flaw was found in Keycloak's OIDC component in the "checkLoginIframe," which allows unvalidated cross-origin messages. This flaw allows attackers to coordinate and send millions of requests in seconds using simple code, significantly impacting the application's availability without proper origin validation for incoming messages.

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.

The undertow client is not checking the server identity presented by the server certificate in https connections. This is a compulsory step (at least it should be performed by default) in https and in http/2. I would add it to any TLS client protocol.