A flaw was found in Undertow where malformed client requests can trigger server-side stream resets without triggering abuse counters. This issue, referred to as the "MadeYouReset" attack, allows malicious clients to induce excessive server workload by repeatedly causing server-side stream aborts. While not a protocol bug, this highlights a common implementation weakness that can be exploited to cause a denial of service (DoS).

A flaw was found in Undertow that can cause remote denial of service attacks. When the server uses the FormEncodedDataDefinition.doParse(StreamSourceChannel) method to parse large form data encoding with application/x-www-form-urlencoded, the method will cause an OutOfMemory issue. This flaw allows unauthorized users to cause a remote denial of service (DoS) attack.

A flaw was found in Undertow. Servlets using a method that calls HttpServletRequestImpl.getParameterNames() can cause an OutOfMemoryError when the client sends a request with large parameter names. This issue can be exploited by an unauthorized user to cause a remote denial-of-service (DoS) attack.

A flaw was found in Undertow. A remote attacker can cause Out of Memory on websockets endpoint without authentication on any @ServerEndpoint class that has any @OnMessage method. This allows an attacker to cause Denial of Service attack without authentication and using only a standard WebSocket handshake.

A vulnerability was found in Undertow where the ProxyProtocolReadListener reuses the same StringBuilder instance across multiple requests. This 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. Undertow 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 an uncontrolled resource consumption leaving the server side to a Denial of Service vulnerability attack. This happens only with Java 17 TLSv1.3 scenarios.

A vulnerability was found in Undertow. This vulnerability requires enabling the learning-push handler in the server's config (it is disabled by default), leave the maxAge config in the handler unconfigured. The default is -1, so it 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.

There exists a security vulnerability in Undertow that can cause remote DoS attacks. When server uses method FormEncodedDataDefinition.doParse(StreamSourceChannel) to parse large form data encoding with application/x-www-form-urlencoded, the method will cause OutOfMemory. This vulnerability can be exploited by unauthorized users to cause remote denial-of-service (DoS) attack.

This happens because there is no size limit for this method hence a large request may jeopardize the environment leading to DoS.