A misconfiguration flaw was found in Keycloak. This issue can allow an attacker to redirect users to an arbitrary URL if a 'Valid Redirect URI' is set to http://localhost or http://127.0.0.1, enabling sensitive information such as authorization codes to be exposed to the attacker, potentially leading to session hijacking.

A flaw exists in the SAML signature validation method within the Keycloak XMLSignatureUtil class. The method incorrectly determines whether a SAML signature is for the full document or only for specific assertions based on the position of the signature in the XML document, rather than the Reference element used to specify the signed element. This flaw allows attackers to create crafted responses that can bypass the validation, potentially leading to privilege escalation or impersonation attacks.

A denial of service vulnerability was found in keycloak where the amount of attributes per object is not limited,an attacker by sending repeated HTTP requests could cause a resource exhaustion when the application send back rows with long attribute values.

A session fixation issue was discovered in the SAML adapters provided by Keycloak. The session ID and JSESSIONID cookie are not changed at login time, even when the turnOffChangeSessionIdOnLogin option is configured. This flaw allows an attacker who hijacks the current session before authentication to trigger session fixation.

A vulnerability was found in Keycloak. Expired OTP codes are still usable when using FreeOTP when the OTP token period is set to 30 seconds (default). Instead of expiring and deemed unusable around 30 seconds in, the tokens are valid for an additional 30 seconds totaling 1 minute. A one time passcode that is valid longer than its expiration time increases the attack window for malicious actors to abuse the system and compromise accounts. Additionally, it increases the attack surface because at any given time, two OTPs are valid.

An open redirect vulnerability was found in Keycloak. A specially crafted URL can be constructed where the referrer and referrer_uri parameters are made to trick a user to visit a malicious webpage. A trusted URL can trick users and automation into believing that the URL is safe, when, in fact, it redirects to a malicious server. This issue can result in a victim inadvertently trusting the destination of the redirect, potentially leading to a successful phishing attack or other types of attacks. Once a crafted URL is made, it can be sent to a Keycloak admin via email for example. This will trigger this vulnerability when the user visits the page and clicks the link. A malicious actor can use this to target users they know are Keycloak admins for further attacks. It may also be possible to bypass other domain-related security checks, such as supplying this as a OAuth redirect uri. The malicious actor can further obfuscate the redirect_uri using URL encoding, to hide the text of the …

A vulnerability was found in Keycloak. This flaw allows attackers to bypass brute force protection by exploiting the timing of login attempts. By initiating multiple login requests simultaneously, attackers can exceed the configured limits for failed attempts before the system locks them out. This timing loophole enables attackers to make more guesses at passwords than intended, potentially compromising account security on affected systems.

A vulnerability was found in Undertow where the ProxyProtocolReadListener reuses the same StringBuilder instance across multiple requests. This issue occurs when the parseProxyProtocolV1 method processes multiple requests on the same HTTP connection. As a result, different requests may share the same StringBuilder instance, potentially leading to information leakage between requests or responses. In some cases, a value from a previous request or response may be erroneously reused, which could lead to unintended data exposure. This issue primarily results in errors and connection termination but creates a risk of data leakage in multi-request environments.

A vulnerability was found in Undertow. This issue requires enabling the learning-push handler in the server's config, which is disabled by default, leaving the maxAge config in the handler unconfigured. The default is -1, which makes the handler vulnerable. If someone overwrites that config, the server is not subject to the attack. The attacker needs to be able to reach the server with a normal HTTP request.

A vulnerability was found in Undertow, where the chunked response hangs after the body was flushed. The response headers and body were sent but the client would continue waiting as Undertow does not send the expected 0\r\n termination of the chunked response. This results in uncontrolled resource consumption, leaving the server side to a denial of service attack. This happens only with Java 17 TLSv1.3 scenarios.