Vulnerability Note VU#366020

Apache mod_tcl module contains a format string error

Original Release date: 07 Nov 2006 | Last revised: 07 Nov 2006


A format string vulnerability exists in the mod_tcl Apache module. This vulnerability may allow a remote attacker to execute arbitrary code.


The Apache HTTP Server, also known as httpd, is an open-source HTTP server that runs on Microsoft Windows, Linux, Unix, and Apple OS X Operating Systems. Apache modules can be used to extend the functionality of the Apache web server. The mod_tcl module is a scripting module that allows Apache to run TCL scripts natively.

There is a format string vulnerability in the mod_tcl module that may allow an attacker to execute arbitrary code.


A remote, unauthenticated attacker may be able to execute arbitrary code with the privileges of the httpd process.


The mod_tcl team has released an upgrade that addresses this issue.

Install only required modules

Only install the modules that are necessary for the operation of the web server.

Restrict access

Restricting access to a vulnerable system to trusted hosts until an upgrade can be applied may mitigate the affects of this vulnerability.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Apache HTTP Server ProjectAffected-07 Nov 2006
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Thanks to the mod_tcl and Gentoo teams for providing information about this vulnerability.

This document was written by Ryan Giobbi.

Other Information

  • CVE IDs: CVE-2006-4154
  • Date Public: 14 Oct 2006
  • Date First Published: 07 Nov 2006
  • Date Last Updated: 07 Nov 2006
  • Severity Metric: 3.99
  • Document Revision: 27


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