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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.007 (51.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.007 · change: -0.004
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
- lists.apache.org/thread/j9vmlc410ht5f28fc98gx75jcbq62j00 (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.