Skip to main content

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')


Severity Low
Score 3.7/10


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 8.5.0 through 8.5.77, 9.0.0-M1 through 9.0.60, 10.0.0-M1 through 10.0.18 and 10.1.0-M1 through 10.1.0-M12 and that could cause client connections to share an "Http11Processor" instance resulting in responses, or part responses, to be received by the wrong client.

  • HIGH
  • NONE
  • NONE
  • NONE
  • LOW
  • NONE

CWE-362 - Race Condition

A race condition occurs in a shared memory program when two threads/processes access the same shared memory data, and at least one thread executes a write operation. This vulnerability manipulates the time to check vs. time to use (TOC/TOU) gap between the threads in the critical section to cause disorientation in the shared data. The impact can vary from compromising the confidentiality of the system to causing the system to crash or to execute arbitrary code.

Advisory Timeline

  • Published