CVE-2026-42253

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.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0111

Probability of exploitation

0.62%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
apache	activemq	< 5.19.7
apache	activemq	6.0.0 — 6.2.6
apache	activemq_web	< 5.19.7
apache	activemq_web	6.0.0 — 6.2.6

References

Advisories & Patches

https://lists.apache.org/thread/j9vmlc410ht5f28fc98gx75jcbq62j00

Other References

http://www.openwall.com/lists/oss-security/2026/05/31/17

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-42253? +

CVE-2026-42253 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0111, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-42253? +

CVE-2026-42253 affects products from apache, specifically: activemq, activemq_web. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-42253? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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