8.1

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

Awaiting analysis
Published 15-09-2026Last modified 17-09-2026

Vulnerability summary

CVE-2026-12666 is a high (CVSS 8.1) vulnerability in ibm mq. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.3% of scored vulnerabilities.

Overall risk
32/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.26%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 15-09-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

17%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.26% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ibm1 product
  • mq≥ 9.1.0.0, ≤ 9.1.0.37 LTS | ≥ 9.2.0.0, ≤ 9.2.0.43 LTS | ≥ 9.3.0.0, ≤ 9.3.0.41 LTS | ≥ 9.3.0.0, ≤ 9.3.5.1 CD | ≥ 9.4.0.0, ≤ 9.4.0.25 LTS | ≥ 9.4.0.0, ≤ 9.4.5.1 CD | 10.0.0.0

1 vendor · 1 product

References

1 links