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PR10-04 - Directory traversal limited to file validation within Viva thumbs WordPress add-on

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Advisories (Vulnerabilities) & Papers

Vulnerability found:
04 February 2010
Vendor informed:
08 February 2010
Severity level:
Richard Brain of ProCheckUp Ltd (
Viva Thumbs resizes and display images, as part of a popular WordPress plugin.ProCheckUp has discovered that Viva Thumbs is vulnerable to a directory traversal attack within the image display functionality, the directory traversal attack is limited to file existence validation.

Note: tested on Viva Thumbs running on the Linux operating system.
Proof of concept:
The following demonstrate the traversal flaw:

1) Vulnerable to directory traversal

The existance of files can be validated on the system, outside the WordPress webroot.
How to fix:
None available
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