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undertow vulnerabilities

Vulnerabilities published for undertow in the last 30 days: 0. Listed in the KEV catalogue: 0.

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Vulnerabilities: 43

  1. CVE-2026-28369

    High · CVSS 8.7EPSS 0.69%No fix published

    Undertow: undertow: request smuggling via malformed http request headers

    A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote attacker to perform request smuggling. Request smuggling allows an attacker to bypass security mechanisms, access restricted information, or manipulate web caches, potentially leading to unauthorized actions or data exposure.

    Published Updated
  2. CVE-2026-28367

    High · CVSS 8.7EPSS 0.72%No fix published

    Undertow: undertow: request smuggling via `\r\r\r` as a header block terminator

    A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\r\r\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

    Published Updated
  3. CVE-2026-28368

    High · CVSS 8.7EPSS 0.73%No fix published

    Undertow: undertow: request smuggling via inconsistent header parsing

    A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks, potentially bypassing security controls and accessing unauthorized resources.

    Published Updated
  4. CVE-2024-4027

    High · CVSS 7.5EPSS 0.4%No fix published

    Undertow: outofmemoryerror in httpservletrequestimpl.getparameternames() can cause remote dos attacks

    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.

    Published Updated
  5. CVE-2025-12543

    Critical · CVSS 9.6EPSS 1.33%No fix published

    Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf

    A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.

    Published Updated
  6. CVE-2024-3884

    High · CVSS 7.5EPSS 1.36%No fix published

    Undertow: outofmemory when parsing form data encoding with application/x-www-form-urlencoded

    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.

    Published Updated
  7. CVE-2025-9784

    High · CVSS 7.5EPSS 2.33%No fix published

    Undertow: undertow madeyoureset http/2 ddos vulnerability

    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).

    Published Updated
  8. CVE-2023-4639

    High · CVSS 7.4EPSS 1.09%No fix published

    Undertow: cookie smuggling/spoofing

    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.

    Published Updated
  9. CVE-2024-7885

    High · CVSS 7.5EPSS 2.64%No fix published

    Undertow: improper state management in proxy protocol parsing causes information leakage

    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

    Published Updated
  10. CVE-2024-3653

    Medium · CVSS 5.3EPSS 1.87%No fix published

    Undertow: learningpushhandler can lead to remote memory dos attacks

    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.

    Published Updated
  11. CVE-2024-5971

    High · CVSS 7.5EPSS 2.92%No fix published

    Undertow: response write hangs in case of java 17 tlsv1.3 newsessionticket

    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.

    Published Updated
  12. CVE-2024-6162

    High · CVSS 7.5EPSS 1.7%No fix published

    Undertow: url-encoded request path information can be broken on ajp-listener

    A vulnerability was found in Undertow, where URL-encoded request paths can be mishandled during concurrent requests on the AJP listener. This issue arises because the same buffer is used to decode the paths for multiple requests simultaneously, leading to incorrect path information being processed. As a result, the server may attempt to access the wrong path, causing errors such as "404 Not Found" or other application failures. This flaw can potentially lead to a denial of service, as legitimate resources become inaccessible due to the path mix-up.

    Published Updated
  13. CVE-2024-1635

    High · CVSS 7.5EPSS 4.57%No fix published

    Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol

    A vulnerability was found in Undertow. This vulnerability impacts a server that supports the wildfly-http-client protocol. Whenever a malicious user opens and closes a connection with the HTTP port of the server and then closes the connection immediately, the server will end with both memory and open file limits exhausted at some point, depending on the amount of memory available. At HTTP upgrade to remoting, the WriteTimeoutStreamSinkConduit leaks connections if RemotingConnection is closed by Remoting ServerConnectionOpenListener. Because the remoting connection originates in Undertow as part of the HTTP upgrade, there is an external la

    Published Updated
  14. CVE-2024-1459

    Medium · CVSS 5.3EPSS 1.71%No fix published

    Undertow: directory traversal vulnerability

    A path traversal vulnerability was found in Undertow. This issue may allow a remote attacker to append a specially-crafted sequence to an HTTP request for an application deployed to JBoss EAP, which may permit access to privileged or restricted files and directories.

    Published Updated
  15. CVE-2023-5379

    High · CVSS 7.5EPSS 1.03%No fix published

    Undertow: ajp request closes connection exceeding maxrequestsize

    A flaw was found in Undertow. When an AJP request is sent that exceeds the max-header-size attribute in ajp-listener, JBoss EAP is marked in an error state by mod_cluster in httpd, causing JBoss EAP to close the TCP connection without returning an AJP response. This happens because mod_proxy_cluster marks the JBoss EAP instance as an error worker when the TCP connection is closed from the backend after sending the AJP request without receiving an AJP response, and stops forwarding. This issue could allow a malicious user could to repeatedly send requests that exceed the max-header-size, causing a Denial of Service (DoS).

    Published Updated
  16. CVE-2023-3223

    High · CVSS 7.5EPSS 2.66%No fix published

    Undertow: outofmemoryerror due to @multipartconfig handling

    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.

    Published Updated

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