CVE Vulnerabilities


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

Published: Oct 25, 2011 | Modified: May 07, 2020
CVSS 3.x
CVSS 2.x

Race condition in Google Chrome before 15.0.874.102 allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to worker process initialization.


The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.

Affected Software

Name Vendor Start Version End Version
Chrome Google * *
Chromium-browser Ubuntu lucid *
Chromium-browser Ubuntu maverick *
Chromium-browser Ubuntu natty *
Chromium-browser Ubuntu oneiric *
Chromium-browser Ubuntu upstream *
Qt4-x11 Ubuntu lucid *
Qtwebkit-source Ubuntu devel *
Qtwebkit-source Ubuntu esm-apps/xenial *
Qtwebkit-source Ubuntu maverick *
Qtwebkit-source Ubuntu natty *
Qtwebkit-source Ubuntu oneiric *
Qtwebkit-source Ubuntu precise *
Qtwebkit-source Ubuntu quantal *
Qtwebkit-source Ubuntu raring *
Qtwebkit-source Ubuntu saucy *
Qtwebkit-source Ubuntu trusty *
Qtwebkit-source Ubuntu utopic *
Qtwebkit-source Ubuntu vivid *
Qtwebkit-source Ubuntu wily *
Qtwebkit-source Ubuntu xenial *
Qtwebkit-source Ubuntu yakkety *
Webkit Ubuntu hardy *
Webkit Ubuntu lucid *
Webkit Ubuntu maverick *
Webkit Ubuntu natty *
Webkit Ubuntu oneiric *
Webkit Ubuntu precise *
Webkit Ubuntu quantal *
Webkit Ubuntu raring *
Webkit Ubuntu saucy *
Webkitgtk Ubuntu utopic *
Webkitgtk Ubuntu vivid *

Extended Description

This can have security implications when the expected synchronization is in security-critical code, such as recording whether a user is authenticated or modifying important state information that should not be influenced by an outsider. A race condition occurs within concurrent environments, and is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:

A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. Programmers may assume that certain code sequences execute too quickly to be affected by an interfering code sequence; when they are not, this violates atomicity. For example, the single “x++” statement may appear atomic at the code layer, but it is actually non-atomic at the instruction layer, since it involves a read (the original value of x), followed by a computation (x+1), followed by a write (save the result to x). The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the program; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable program.

Potential Mitigations

  • Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring.
  • Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).