What is CVE-2026-86243?

CVE-2026-86243 is a high-severity vulnerability in Apache Software Foundation Tomcat Native, classified under Buffer Over-read. CVSS score: 7.5/10. Published 2026-09-23.

How severe is CVE-2026-86243?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Apache Software Foundation Tomcat Native

CVE-2026-86243

Buffer over-read vulnerability in Apache Tomcat Native during the TLS handshake permits a malicious user to trigger a DoS via a JVM crash. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Earlier, unsupported versions may also be affected. Users are recommended to upgrade to version 1.3.9 or 2.0.16, which fix the issue.

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

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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-126 — Buffer Over-read

References

lists.apache.org/thread/8p4jf02w54m22x0cwpq2x53w3ov8o557 (vendor-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-86243?: CVE-2026-86243 is a high-severity vulnerability in Apache Software Foundation Tomcat Native, classified under Buffer Over-read. CVSS score: 7.5/10. Published 2026-09-23.
How severe is CVE-2026-86243?: High severity. CVSS v3 base score is 7.5 out of 10.