Vulnerability · Published Sep 15, 2026 · Assigned by ibm

CVE-2026-12666IBM MQ Java messaging is vulnerable to XML external entity injection

High 8.1

In plain English

A high-severity XML external entity in MQ from IBM. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.5%top 59.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
IBM MQ 9.1.0.0 – through 9.1.0.37 LTS9.2.0.0 – through 9.2.0.43 LTS9.3.0.0 – through 9.3.0.41 LTS9.3.0.0 – through 9.3.5.1 CD9.4.0.0 – through 9.4.0.25 LTS9.4.0.0 – through 9.4.5.1 CD10.0.0.0

Weakness: CWE-611 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

References