What is CVE-2026-42498?

CVE-2026-42498 is a high-severity vulnerability in Apache Tomcat, classified under Information Disclosure. CVSS score: 7.3/10. Published 2026-05-12.

How severe is CVE-2026-42498?

High severity. CVSS v3 base score is 7.3 out of 10.

Information disclosure in Apache Tomcat

CVE-2026-42498

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.

Vulnerability class: Information Disclosure

Published 2026-05-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.006 (48.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000

Affected products

Apache Tomcat
Apache Software Foundation Tomcat — versions 11.0.0-M1, 10.1.0-M1, 9.0.2

Weakness classification (CWE)

CWE-200 — Information Disclosure

References

lists.apache.org/thread/n61zwf75jrv09rz90j4jssncm244bwdb (vendor-advisory, Mailing List, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-42498?: CVE-2026-42498 is a high-severity vulnerability in Apache Tomcat, classified under Information Disclosure. CVSS score: 7.3/10. Published 2026-05-12.
How severe is CVE-2026-42498?: High severity. CVSS v3 base score is 7.3 out of 10.