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CERT Coordination Center

DansGuardian content filtering proxy fails to adequately validate user input thereby allowing user to access restricted site via hex encoded URLs

Vulnerability Note VU#940203

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


DansGuardian does not properly filter


DansGuardian is an HTTP proxy server based on Squid and enhanced to filter web content. DansGuardian does not properly process URLs that contain certain unspecified hexadecimal encodings, resulting in incomplete filtering of HTTP responses. Users may be able to violate security policies or inadvertently access malicious code by following a malicious web link or requesting a malicious URL.


Security policies may be violated and malicious code may be accessed.



Upgrade to version 2.4.5-1 of DansGuardian:

Vendor Information

Affected   Unknown   Unaffected

Daniel Barron

Updated:  September 24, 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 DansGuardian for reporting this vulnerability.

This document was written by Shawn Van Ittersum.

Other Information

CVE IDs: None
Severity Metric: 1.32
Date Public: 2002-07-22
Date First Published: 2002-09-26
Date Last Updated: 2002-09-26 22:05 UTC
Document Revision: 3

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