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

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-01 · updated 2026-07-22
Weakness: CWE-79

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.

Affected products

Apache ActiveMQ: before 5.19.7; from 6.0.0 before 6.2.6 — fixed in 5.19.7, 6.2.6
Apache Activemq Web: before 5.19.7; from 6.0.0 before 6.2.6 — fixed in 5.19.7, 6.2.6

How to fix

Upgrade to a fixed version: Apache ActiveMQ 5.19.7, 6.2.6; Apache Activemq Web 5.19.7, 6.2.6. Check the vendor advisory for mitigations.

References

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