--- 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) 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 published: '2026-08-11' updated: '2026-09-22' sourceUpdated: '2026-09-22T16:17:44.833' 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/errata/RHSA-2026:70228' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:70229' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:70230' 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 epss: 0.00592 epssPercentile: 0.47022 ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-08-11T17:48:42.989579Z' ingestedAt: '2026-09-17T19:26:25.290Z' --- ## Overview 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. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **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) - **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) - **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) - **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 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 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-15565.json) - **RHSA-2026:70230** · Red Hat · fixed in: Red Hat JBoss EAP 8.1 for RHEL 10 · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:70230) - **RHSA-2026:70228** · Red Hat · fixed in: Red Hat JBoss EAP 8.1 for RHEL 8 · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:70228) - **RHSA-2026:70229** · Red Hat · fixed in: Red Hat JBoss EAP 8.1 for RHEL 9 · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:70229)