XSS in Apache Activemq
CVE-2026-42253
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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.011 (63.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Apache Activemq
- Apache Activemq_web
- Apache Software Foundation Activemq — versions 0, 6.0.0
- Apache Software Foundation Activemq Web — versions 0, 6.0.0
Weakness classification (CWE)
References
- security@apache.org (vendor-advisory, Mailing List, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-42253?
- CVE-2026-42253 is a medium-severity vulnerability in Apache Activemq, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-01.
- How severe is CVE-2026-42253?
- Medium severity. CVSS v3 base score is 6.1 out of 10.