What is CVE-2026-12538?

CVE-2026-12538 is a medium-severity vulnerability in IBM Mq Appliance, classified under Buffer Underwrite. CVSS score: 5.4/10. Published 2026-11-04.

How severe is CVE-2026-12538?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Vulnerability in IBM Mq Appliance

CVE-2026-12538

IBM MQ 9.4.0.0 to 9.4.0.26, 9.4.1.0 to 9.4.5.3, and 10.0.0.1 to 10.0.0.5 could allow an authenticated attacker to obtain sensitive information or cause a denial of service due to improper validation of message header structure length fields.

Published 2026-11-04 · last modified 2026-11-04.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

IBM Mq Appliance

Weakness classification (CWE)

CWE-124 — Buffer Underwrite

References

www.ibm.com/support/pages/node/7293035 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-12538?: CVE-2026-12538 is a medium-severity vulnerability in IBM Mq Appliance, classified under Buffer Underwrite. CVSS score: 5.4/10. Published 2026-11-04.
How severe is CVE-2026-12538?: Medium severity. CVSS v3 base score is 5.4 out of 10.