What is CVE-2026-86247?

CVE-2026-86247 is a high-severity vulnerability in Apache Software Foundation Tomcat Native, classified under Race Condition within a Thread. CVSS score: 7.4/10. Published 2026-09-23.

How severe is CVE-2026-86247?

High severity. CVSS v3 base score is 7.4 out of 10.

Vulnerability in Apache Software Foundation Tomcat Native

CVE-2026-86247

Race condition within a thread vulnerability in Apache Tomcat Native allowed client certificate verification requirements to be down-graded for some configurations. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Unsupported versions may also be affected. Users are recommended to upgrade to version 2.0.16 or 1.3.9, which fixes the issue.

Published 2026-09-23 · last modified 2026-09-23.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.

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

Apache Software Foundation Tomcat Native

Weakness classification (CWE)

CWE-366 — Race Condition within a Thread

References

lists.apache.org/thread/obsson6zhvfg0wsp2bx602l61ltj87r1 (vendor-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-86247?: CVE-2026-86247 is a high-severity vulnerability in Apache Software Foundation Tomcat Native, classified under Race Condition within a Thread. CVSS score: 7.4/10. Published 2026-09-23.
How severe is CVE-2026-86247?: High severity. CVSS v3 base score is 7.4 out of 10.