What is CVE-2026-78437?

CVE-2026-78437 is a high-severity vulnerability in Apache Software Foundation Tomcat, classified under Incomplete Cleanup. CVSS score: 7.3/10. Published 2026-09-23.

How severe is CVE-2026-78437?

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

Vulnerability in Apache Software Foundation Tomcat

CVE-2026-78437

Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail. This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

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

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

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

Weakness classification (CWE)

CWE-459 — Incomplete Cleanup

References

lists.apache.org/thread/qkmsos3s8chn5053qr466rzwv6sk5gjg (vendor-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-78437?: CVE-2026-78437 is a high-severity vulnerability in Apache Software Foundation Tomcat, classified under Incomplete Cleanup. CVSS score: 7.3/10. Published 2026-09-23.
How severe is CVE-2026-78437?: High severity. CVSS v3 base score is 7.3 out of 10.