CVE-2026-78437

Apache Tomcat: HTTP/2 DoS via malformed request

State: Published
Severity: 7.3 High
Published: Sep 23, 2026
Updated: Sep 23, 2026
Reserved: Aug 24, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.3 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	CISA-ADP

Weaknesses

CWE-459 Incomplete cleanup

Affected Products

Product	Versions
Apache TomcatApache Software Foundation	11.0.19 through 11.0.25Affected 10.1.53 through 10.1.59Affected 9.0.116 through 9.0.121Affected 8.5.100 and earlierNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.