CVE-2026-77762 PUBLISHED

Apache Tomcat: Stale HPACK emitter injects trailers into recycled pooled Request

Assigner: apache
Reserved: 21.08.2026 Published: 23.09.2026 Updated: 23.09.2026

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.

Product Status

Vendor Apache Software Foundation
Product Apache Tomcat
Versions Default: unaffected
  • affected from 11.0.0-M1 to 11.0.25 (incl.)
  • affected from 10.1.0-M1 to 10.1.59 (incl.)
  • affected from 9.0.39 to 9.0.121 (incl.)
  • affected from 8.56.59 to 8.5.100 (incl.)
  • unaffected from 0 to 7.0.109 (incl.)

References

Problem Types

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') CWE