CVE-2026-12666: IBM MQ Java messaging is vulnerable to XML external entity injection
IBM MQ 9.1.0.0 through 9.1.0.37 LTS, 9.2.0.0 through 9.2.0.43 LTS, 9.3.0.0 through 9.3.0.41 LTS, 9.3.0.0 through 9.3.5.1 CD, 9.4.0.0 through 9.4.0.25 LTS, 9.4.0.0 through 9.4.5.1 CD, and 10.0.0.0 Classes for Java could allow an authenticated attacker to obtain sensitive information or cause a denial of service due to XML external entity injection in MQRFH2 header processing.
Other sources
IBM MQ Classes for Java could allow an authenticated attacker to obtain sensitive information or cause a denial of service due to XML external entity injection in MQRFH2 header processing.
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
IBM MQ 9.1 LTSto a version that resolves this vulnerability.Fixed in 9.1.0.38 - Upgrade
Upgrade
IBM MQ 9.2 LTSto a version that resolves this vulnerability.Fixed in 9.2.0.44 - Upgrade
Upgrade
IBM MQ 9.3 LTSto a version that resolves this vulnerability.Fixed in 9.3.0.42 - Upgrade
Upgrade
IBM MQ 9.4 LTSto a version that resolves this vulnerability.Fixed in 9.4.0.26 - Upgrade
Upgrade
IBM MQ 10.0.0 Classes for Javato a version that resolves this vulnerability.Fixed in 10.0.0.5 - Compensating control
If you cannot upgrade immediately, address the vulnerability tracked under Known Issue DT474364 as referenced by the IBM advisory until the relevant cumulative security update/upgrade is applied.
Event History
Frequently Asked Questions
What access does an attacker need to exploit this issue?
An attacker must be authenticated and able to target MQRFH2 header processing through IBM MQ Classes for Java. The vector is network-accessible, requires low attack complexity, and does not require user interaction.
What is the practical impact?
Successful exploitation may allow an authenticated attacker to obtain sensitive information or cause a denial of service. The provided severity vector indicates high confidentiality impact and high availability impact, with no integrity impact.
Which releases are affected?
Affected releases include IBM MQ 9.1.0.0 through 9.1.0.37 LTS; 9.2.0.0 through 9.2.0.43 LTS; 9.3.0.0 through 9.3.0.41 LTS and 9.3.0.0 through 9.3.5.1 CD; 9.4.0.0 through 9.4.0.25 LTS and 9.4.0.0 through 9.4.5.1 CD; and IBM MQ 10.0.0.0 Classes for Java.