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CERT Coordination Center

WebCalendar does not adequately validate user input

Vulnerability Note VU#951632

Original Release Date: 2002-09-26 | Last Revised: 2002-09-26


WebCalendar does not properly validate user input, allowing attackers to execute arbitrary commands.


WebCalendar is a free PHP application providing web calendar services for user groups. WebCalendar contains an unspecified input validation vulnerability, allowing arbitrary command execution by a malicious WebCalendar user. If WebCalendar is configured in "single-user mode" (a non-default configuration), attackers do not need a WebCalendar account to exploit this vulnerability.


Malicious users can execute arbitrary commands on the server.


The CERT/CC is currently unaware of a practical solution to this problem.

An unofficial patch is available from Secure Reality:

Vendor Information

Expand all

Craig Knudsen

Updated:  September 23, 2002



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

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



Thanks to Asher Glynn for reporting this vulnerability.

This document was written by Shawn Van Ittersum.

Other Information

CVE IDs: None
Severity Metric: 4.28
Date Public: 2001-04-23
Date First Published: 2002-09-26
Date Last Updated: 2002-09-26 21:58 UTC
Document Revision: 5

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