Incorrect Synchronization Affecting org.apache.tomcat.embed:tomcat-embed-core package, versions [9.0.39,9.0.122)[10.1.0-M1,10.1.60)[11.0.0-M1,11.0.26)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Incorrect Synchronization vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-JAVA-ORGAPACHETOMCATEMBED-21716513
- published26 Oct 2026
- disclosed23 Sept 2026
- creditUnknown
Introduced: 23 Sep 2026
CVE-2026-77762 (opens in a new tab)How to fix?
Upgrade org.apache.tomcat.embed:tomcat-embed-core to version 9.0.122, 10.1.60, 11.0.26 or higher.
Overview
org.apache.tomcat.embed:tomcat-embed-core is a Core Tomcat implementation.
Affected versions of this package are vulnerable to Incorrect Synchronization via the shared header emitter in the HTTP/2 HpackDecoder. An attacker can inject trailer fields into another HTTP/2 request by sending requests that cause a stream to be reset and replaced while headers are being decoded, making the server process the other request with attacker-supplied trailer data.
Notes
- At the decoder-to-request handoff, the affected and attacker-controlled streams must be on the same HTTP/2 connection, whose
HpackDecodershares the header emitter.