CVE-2026-77762: CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in Apache Software Foundation Apache Tomcat
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.
AI Analysis
Technical Summary
CVE-2026-77762 is a concurrency issue in Apache Tomcat where improper synchronization of shared resources leads to a race condition. This flaw enables an attacker to inject trailer fields into a different HTTP/2 request, potentially impacting request integrity. The vulnerability affects Apache Tomcat versions from 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, 9.0.39 through 9.0.121, and some 8.5.x versions from 8.5.59 through 8.5.100. The Apache Software Foundation has addressed this issue in versions 11.0.26, 10.1.60, and 9.0.122.
Potential Impact
An attacker exploiting this race condition can inject trailer fields into another HTTP/2 request, which may lead to unexpected behavior or security issues related to HTTP/2 request processing. The exact impact beyond injection of trailer fields is not detailed in the provided data.
Mitigation Recommendations
Users should upgrade affected Apache Tomcat instances to versions 11.0.26, 10.1.60, or 9.0.122 or later, where this race condition vulnerability has been fixed. No other mitigation or temporary workaround is indicated.
CVE-2026-77762: CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in Apache Software Foundation Apache Tomcat
Description
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.
CVSS v3.1
Score 8.1high
Affected software
Apache Software Foundation
Apache Tomcat
pkg:maven/org.apache.tomcat/tomcatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-77762 is a concurrency issue in Apache Tomcat where improper synchronization of shared resources leads to a race condition. This flaw enables an attacker to inject trailer fields into a different HTTP/2 request, potentially impacting request integrity. The vulnerability affects Apache Tomcat versions from 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, 9.0.39 through 9.0.121, and some 8.5.x versions from 8.5.59 through 8.5.100. The Apache Software Foundation has addressed this issue in versions 11.0.26, 10.1.60, and 9.0.122.
Potential Impact
An attacker exploiting this race condition can inject trailer fields into another HTTP/2 request, which may lead to unexpected behavior or security issues related to HTTP/2 request processing. The exact impact beyond injection of trailer fields is not detailed in the provided data.
Mitigation Recommendations
Users should upgrade affected Apache Tomcat instances to versions 11.0.26, 10.1.60, or 9.0.122 or later, where this race condition vulnerability has been fixed. No other mitigation or temporary workaround is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-08-21T10:14:30.089Z
- State
- PUBLISHED
Threat ID: 6ab3b90ff7a7c54106b30f1d
Added to database: 09/23/2026, 11:33:35 UTC
Last enriched: 09/23/2026, 11:48:05 UTC
Last updated: 09/24/2026, 03:13:44 UTC
Views: 14
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