Bug 2539533 (CVE-2026-78437)

Summary:	CVE-2026-78437 tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	csutherl, dsoumis, jclere, jwon, pjindal, plodge, rhel-process-autobot, rmaucher, szappis, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Apache Tomcat. An incomplete cleanup vulnerability allows a remote attacker to send a malformed HTTP/2 request. This can potentially cause a denial of service, leading to one request from another user failing.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2543044
Bug Blocks:

Description OSIDB Bzimport 2026-09-23 16:49:59 UTC

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.