{"id":"CVE-2026-15565","title":"A flaw was found in Undertow","summary":"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 …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-120"],"vendor":"Red Hat","product":"eap7-activemq-artemis","affected":["eap7-activemq-artemis (all versions)","eap7-glassfish-jsf (all versions)","eap7-ironjacamar (all versions)","eap7-jackson-annotations (all versions)","eap7-jackson-core (all versions)","eap7-jackson-databind (all versions)","eap7-jackson-jaxrs-providers (all versions)","eap7-jackson-modules-base (all versions)","eap7-jackson-modules-java8 (all versions)","eap7-jboss-remoting (all versions)","eap7-jboss-server-migration (all versions)","eap7-netty (all versions)","eap7-netty-transport-native-epoll (all versions)","eap7-picketlink-bindings (all versions)","eap7-picketlink-federation (all versions)","eap7-undertow (all versions)","eap7-wildfly (all versions)","eap7-activemq-artemis (all versions)","eap7-glassfish-jsf (all versions)","eap7-ironjacamar (all versions)","eap7-jackson-annotations (all versions)","eap7-jackson-core (all versions)","eap7-jackson-databind (all versions)","eap7-jackson-jaxrs-providers (all versions)","eap7-jackson-modules-base (all versions)","eap7-jackson-modules-java8 (all versions)","eap7-jboss-remoting (all versions)","eap7-jboss-server-migration (all versions)","eap7-netty (all versions)","eap7-netty-transport-native-epoll (all versions)","eap7-picketlink-bindings (all versions)","eap7-picketlink-federation (all versions)","eap7-undertow (all versions)","eap7-wildfly (all versions)","eap7-activemq-artemis (all versions)","eap7-glassfish-jsf (all versions)","eap7-ironjacamar (all versions)","eap7-jackson-annotations (all versions)","eap7-jackson-core (all versions)","eap7-jackson-databind (all versions)","eap7-jackson-jaxrs-providers (all versions)","eap7-jackson-modules-base (all versions)","eap7-jackson-modules-java8 (all versions)","eap7-jboss-remoting (all versions)","eap7-jboss-server-migration (all versions)","eap7-netty (all versions)","eap7-netty-transport-native-epoll (all versions)","eap7-picketlink-bindings (all versions)","eap7-picketlink-federation (all versions)","eap7-undertow (all versions)"],"published":"2026-08-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T00:16:56.580","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-15565","references":[{"url":"https://access.redhat.com/errata/RHSA-2026:53644","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:53645","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:53646","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:53806","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-15565","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2490628","label":"secalert@redhat.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-15565.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-15565"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-15565"},{"url":"https://cwe.mitre.org/data/definitions/120.html"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-08-11T17:48:42.989579Z"},"epss":0.0051,"epssPercentile":0.42378,"ingestedAt":"2026-09-17T19:26:25.290Z","patched":["jboss_eap_7_4_els_for_rhel_7_server","jboss_eap_7_4_els_for_rhel 8","jboss_eap_7_4_els_for_rhel 9"],"slug":"CVE-2026-15565","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:53644** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 7 Server · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53644)\n- **RHSA-2026:53645** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 8 · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53645)\n- **RHSA-2026:53646** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 9 · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53646)\n- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 8, Red Hat Single Sign-On 7 · no fix planned: Red Hat Fuse 7, Red Hat Single Sign-On 7, Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, … · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-15565.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}