Bug 2539353 (CVE-2026-77762)

Summary: CVE-2026-77762 tomcat: Apache Tomcat: Race condition allows HTTP/2 request manipulation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: csutherl, dsoumis, jclere, jwon, pjindal, plodge, rhel-process-autobot, rmaucher, szappis, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Apache Tomcat. This vulnerability, caused by a race condition during concurrent execution, allows an attacker to inject unauthorized data, known as trailer fields, into another user's HTTP/2 request. This could lead to the manipulation of web traffic or unintended information disclosure.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2543044    
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Description OSIDB Bzimport 2026-09-23 11:33:09 UTC
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat allows an attacker to inject trailer fields into another HTTP/2 request.



This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.39 through 9.0.121.



The following versions were EOL at the time the CVE was created but are 
known to be affected: from 8.5.59 through 8.5.100. Other unsupported versions may also be affected.




Users are recommended to upgrade to version 11.0.26, 10.1.60, 9.0.122, which fix the issue.