CVE-2026-12666 is a vulnerability in IBM Mq

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.

Vulnerability Analysis

CVE-2026-12666 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and a high impact on availability.

Attack Vector:

NETWORK

Attack Complexity:

LOW

Privileges Required:

LOW

User Interaction:

NONE

Scope:

UNCHANGED

Confidentiality Impact:

HIGH

Integrity Impact:

NONE

Availability Impact:

HIGH

Weakness Type

What is a XXE Vulnerability?

The software processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

CVE-2026-12666 has been classified to as a XXE vulnerability or weakness.

Products Associated with CVE-2026-12666

Want to know whenever a new CVE is published for IBM Mq? stack.watch will email you.

Affected Versions

Exploit Probability

EPSS

0.26%

Percentile

16.42%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.