Undertow
Monthly
Undertow HTTP server (used in WildFly, JBoss EAP) fails to validate Host headers, enabling cache poisoning, internal network scanning, and session hijacking. Affects a widely-used Java application server component.
Undertow, a Java web server used across Red Hat's JBoss Enterprise Application Platform, Fuse, and other middleware products, contains a vulnerability that allows attackers to trigger server-side HTTP/2 stream resets without incrementing abuse counters. This 'MadeYouReset' attack enables remote unauthenticated attackers to cause denial of service by repeatedly forcing the server to abort streams and perform unnecessary cleanup work. With an EPSS score of 1.17% (78th percentile), exploitation probability is moderate but rising, and patches have been released across multiple Red Hat product lines as of early 2025.
A path traversal vulnerability was found in Undertow. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
When a POST request comes through AJP and the request exceeds the max-post-size limit (maxEntitySize), Undertow's AjpServerRequestConduit implementation closes a connection without sending any. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A flaw was discovered in all versions of Undertow before Undertow 2.2.0.Final, where HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A flaw was discovered in Undertow in versions before Undertow 2.1.1.Final where certain requests to the "Expect: 100-continue" header may cause an out of memory error. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow in versions before 2.1.1.Final, regarding the processing of invalid HTTP requests with large chunk sizes. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A file inclusion vulnerability was found in the AJP connector enabled with a default AJP configuration port of 8009 in Undertow version 2.0.29.Final and before and was fixed in 2.0.30.Final. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in all undertow-2.x.x SP1 versions prior to undertow-2.0.30.SP1, all undertow-1.x.x and undertow-2.x.x versions prior to undertow-2.1.0.Final, where the Servlet container causes. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A flaw was found in, all under 2.0.20, in the Undertow DEBUG log for io.undertow.request.security. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
undertow before version 2.0.23.Final is vulnerable to an information leak issue. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
A vulnerability was found in Undertow web server before 2.0.21. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An information leak vulnerability was found in Undertow. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
It was found that URLResource.getLastModified() in Undertow closes the file descriptors only when they are finalized which can cause file descriptors to exhaust. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
In Undertow before versions 7.1.2.CR1, 7.1.2.GA it was found that the fix for CVE-2016-4993 was incomplete and Undertow web server is vulnerable to the injection of arbitrary HTTP headers, and also. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Directory traversal vulnerability in JBoss Undertow 1.0.x before 1.0.17, 1.1.x before 1.1.0.CR5, and 1.2.x before 1.2.0.Beta3, when running on Windows, allows remote attackers to read arbitrary files. Rated medium severity (CVSS 5.0), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 55.2%.
Undertow HTTP server (used in WildFly, JBoss EAP) fails to validate Host headers, enabling cache poisoning, internal network scanning, and session hijacking. Affects a widely-used Java application server component.
Undertow, a Java web server used across Red Hat's JBoss Enterprise Application Platform, Fuse, and other middleware products, contains a vulnerability that allows attackers to trigger server-side HTTP/2 stream resets without incrementing abuse counters. This 'MadeYouReset' attack enables remote unauthenticated attackers to cause denial of service by repeatedly forcing the server to abort streams and perform unnecessary cleanup work. With an EPSS score of 1.17% (78th percentile), exploitation probability is moderate but rising, and patches have been released across multiple Red Hat product lines as of early 2025.
A path traversal vulnerability was found in Undertow. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
When a POST request comes through AJP and the request exceeds the max-post-size limit (maxEntitySize), Undertow's AjpServerRequestConduit implementation closes a connection without sending any. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A flaw was discovered in all versions of Undertow before Undertow 2.2.0.Final, where HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A flaw was discovered in Undertow in versions before Undertow 2.1.1.Final where certain requests to the "Expect: 100-continue" header may cause an out of memory error. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in Undertow in versions before 2.1.1.Final, regarding the processing of invalid HTTP requests with large chunk sizes. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A file inclusion vulnerability was found in the AJP connector enabled with a default AJP configuration port of 8009 in Undertow version 2.0.29.Final and before and was fixed in 2.0.30.Final. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A flaw was found in all undertow-2.x.x SP1 versions prior to undertow-2.0.30.SP1, all undertow-1.x.x and undertow-2.x.x versions prior to undertow-2.1.0.Final, where the Servlet container causes. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A flaw was found in, all under 2.0.20, in the Undertow DEBUG log for io.undertow.request.security. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
undertow before version 2.0.23.Final is vulnerable to an information leak issue. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
A vulnerability was found in Undertow web server before 2.0.21. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An information leak vulnerability was found in Undertow. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
It was found that URLResource.getLastModified() in Undertow closes the file descriptors only when they are finalized which can cause file descriptors to exhaust. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
In Undertow before versions 7.1.2.CR1, 7.1.2.GA it was found that the fix for CVE-2016-4993 was incomplete and Undertow web server is vulnerable to the injection of arbitrary HTTP headers, and also. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Directory traversal vulnerability in JBoss Undertow 1.0.x before 1.0.17, 1.1.x before 1.1.0.CR5, and 1.2.x before 1.2.0.Beta3, when running on Windows, allows remote attackers to read arbitrary files. Rated medium severity (CVSS 5.0), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 55.2%.