CVE-2026-42253 Apache ActiveMQ, Apache ActiveMQ Web: HTTP Response Header Injection via JMS Message Properties

What is CVE-2026-42253?

CVE-2026-42253 is a medium-severity cross-site scripting vulnerability in Apache Activemq, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Apache ActiveMQ, Apache ActiveMQ Web.

The MessageServlet in the ActiveMQ web console API copies every JMS message property into an HTTP response header without any validation. This can allow overwriting and injecting security headers by setting them on JMS messages that are returned by the servlet.

This issue affects Apache ActiveMQ: before 5.19.7, from 6.0.0 before 6.2.6; Apache ActiveMQ Web: before 5.19.7, from 6.0.0 before 6.2.6.

Users are recommended to upgrade to version 5.19.7 or 6.2.6, which fixes the issue. The MessageServlet has now been deprecated and disabled by default.

Weakness: CWE-79

Which versions are affected by CVE-2026-42253?

9 open source packages ship an affected version, including org.apache.activemq:activemq-web, activemq and org.apache.activemq:apache-activemq. It affects 2 products.

Products include Apache Activemq, Apache Activemq Web.

How do I fix CVE-2026-42253?

Upgrade org.apache.activemq:activemq-web to a fixed version for your release line: 5.19.7 or 6.2.6.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-42253 being exploited?

There is no known exploitation of CVE-2026-42253 in the wild and no public exploit code.

Other vulnerabilities in Apache Activemq

• CVE-2023-46604 Apache ActiveMQ Deserialization of Untrusted Data Exploited Critical 10.0
• CVE-2016-3088 Apache ActiveMQ Improper Input Validation Exploited Critical 9.8
• CVE-2026-34197 Apache ActiveMQ Improper Input Validation Exploited High 8.8
• CVE-2020-11998 Remote code execution in Apache ActiveMQ Critical 9.8
• CVE-2013-7285 Command Injection in Xstream Critical 9.8

All Apache Activemq vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-activemq-2026-42253, DEBIAN-CVE-2026-42253, GHSA-8wm6-6fqh-phmc, MINI-2m22-g7jx-cchc, MINI-46vv-vwv8-cq6r, MINI-5h6m-q7c6-qcrp and 2 more.