What is CVE-2026-11538?

CVE-2026-11538 is a low-severity vulnerability in IBM Websphere Application Server, classified under Improper Output Neutralization for Logs. CVSS score: 3.7/10. Published 2026-09-18.

How severe is CVE-2026-11538?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in IBM Websphere Application Server

CVE-2026-11538

IBM WebSphere Application Server 9.0 and 8.5 is affected by a log injection vulnerability through crafted LTPA token cookies.

Published 2026-09-18 · last modified 2026-09-24.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (5.5th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 5.5% 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: 0.002 · change: 0.000

Affected products

IBM Websphere Application Server — versions 8.5, 9.0
IBM Websphere Application Server

Weakness classification (CWE)

CWE-117 — Improper Output Neutralization for Logs

References

www.ibm.com/support/pages/node/7286610 (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-11538?: CVE-2026-11538 is a low-severity vulnerability in IBM Websphere Application Server, classified under Improper Output Neutralization for Logs. CVSS score: 3.7/10. Published 2026-09-18.
How severe is CVE-2026-11538?: Low severity. CVSS v3 base score is 3.7 out of 10.