What is CVE-2026-11549?

CVE-2026-11549 is a medium-severity vulnerability in IBM Cics Tx Advanced, classified under Improper Access Control. CVSS score: 6.5/10. Published 2026-09-18.

How severe is CVE-2026-11549?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in IBM Cics Tx Advanced

CVE-2026-11549

IBM WebSphere Application Server 8.5 and 9.0, and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.8 are affected by a virtual host bypass vulnerability.

Published 2026-09-18 · last modified 2026-10-22.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (25.8th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

IBM Cics Tx Advanced — versions 10.1
IBM Websphere Application Server — versions 8.5, 9.0
IBM Websphere Application Server - Liberty

Weakness classification (CWE)

CWE-284 — Improper Access Control

References

www.ibm.com/support/pages/node/7287740 (vendor-advisory, patch)
www.ibm.com/support/pages/node/7286610 (vendor-advisory, patch)
www.ibm.com/support/pages/node/7286611 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-11549?: CVE-2026-11549 is a medium-severity vulnerability in IBM Cics Tx Advanced, classified under Improper Access Control. CVSS score: 6.5/10. Published 2026-09-18.
How severe is CVE-2026-11549?: Medium severity. CVSS v3 base score is 6.5 out of 10.