Race Condition Affecting tomcat9 package, versions *


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.16% (38th percentile)

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 applications

Snyk Learn

Learn about Race Condition vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-UBUNTU2204-TOMCAT9-3035660
  • published22 Aug 2025
  • disclosed28 Sept 2022

Introduced: 28 Sep 2022

CVE-2021-43980  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

There is no fixed version for Ubuntu:22.04 tomcat9.

NVD Description

Note: Versions mentioned in the description apply only to the upstream tomcat9 package and not the tomcat9 package as distributed by Ubuntu. See How to fix? for Ubuntu:22.04 relevant fixed versions and status.

The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.

CVSS Base Scores

version 3.1