Description
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).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7 | — | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7 | — | — |
| Red Hat | Red Hat build of Quarkus | — | — |
| Red Hat | Red Hat Data Grid 8 | — | — |
| Red Hat | Red Hat Decision Manager 7 | — | — |
| Red Hat | Red Hat Fuse 7 | — | — |
| Red Hat | Red Hat JBoss Data Grid 7 | — | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | — | — |
| Red Hat | Red Hat JBoss Fuse 6 | — | — |
| Red Hat | Red Hat Process Automation 7 | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
| Red Hat | Red Hat support for Spring Boot | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | undertow | 2.3.18-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | undertow | No fix yet | — |
| Ubuntu 26.04 LTS | undertow | No fix yet | — |
| Ubuntu 25.10 | undertow | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | undertow | No fix yet | — |
| Ubuntu Pro 22.04 LTS | undertow | No fix yet | — |
| Ubuntu Pro 20.04 LTS | undertow | No fix yet | — |
| Ubuntu Pro 18.04 LTS | undertow | No fix yet | — |
| Ubuntu Pro 16.04 LTS | undertow | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-glassfish-el +1 | 3.0.1-4.b08_redhat_00005.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-hibernate +5 | 5.1.17-3.Final_redhat_00004.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jackson-core +4 | 2.10.4-3.redhat_00006.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jackson-databind | 2.8.11.6-3.SP1_redhat_00003.1.ep7.el7 | RHSA-2025:9583, RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jackson-datatype-jdk8 +2 | 2.10.4-2.redhat_00006.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jackson-modules-base +1 | 2.10.4-5.redhat_00006.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jboss-ejb-client | 4.0.12-1.Final_redhat_00002.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-jboss-server-migration +21 | 1.7.2-16.Final_redhat_00017.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-netty +1 | 4.1.63-2.Final_redhat_00003.1.ep7.el7 | RHSA-2025:9583, RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-undertow | 1.4.18-16.SP14_redhat_00001.1.ep7.el7 | RHSA-2025:9583, RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly +1 | 7.1.11-4.GA_redhat_00002.1.ep7.el7 | RHSA-2025:9583, RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-elytron | 1.1.14-1.Final_redhat_00001.1.ep7.el7 | RHSA-2025:9583, RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-elytron-tool | 1.10.17-1.Final_redhat_00001.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-http-client +4 | 1.0.21-1.Final_redhat_00001.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-javadocs +2 | 7.3.14-3.GA_redhat_00002.1.el7eap | RHSA-2025:9583 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-naming-client | 1.0.13-1.Final_redhat_00001.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-openssl +1 | 1.0.12-1.Final_redhat_00001.1.ep7.el7 | RHSA-2025:9582 |
| Red Hat Jboss Enterprise Application Platform Eus 7 | eap7-wildfly-openssl-linux | 1.0.12-6.Final_redhat_00001.1.ep7.el7 | RHSA-2025:9582 |
Advisories 3
- RHSA-2025:9583 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.3.14 Security update Red Hat Security Advisories (RHSA) · Oct 14, 2026
- RHSA-2025:9582 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.1.11 on RHEL 7 security update Red Hat Security Advisories (RHSA) · Oct 14, 2026
- WID-SEC-2025-1203 NetApp ActiveIQ Unified Manager: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Jun 1, 2025
References
- RHSA-2025:9582 vendor-advisory
- RHSA-2025:9583 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2023-5379 vdb-entry
- RHBZ#2242099 issue-tracking