DokuWiki: Cross-site scripting vulnerability

Background

DokuWiki is a simple to use wiki aimed at creating documentation.

Description

DokuWiki does not sanitize user input to the GET variable ‘media’ in the fetch.php file.

Impact

An attacker could entice a user to click a specially crafted link and inject CRLF characters into the variable. This would allow the creation of new lines or fields in the returned HTTP Response header, which would permit the attacker to execute arbitrary scripts in the context of the user’s browser.

Workaround

Replace the following line in lib/exe/fetch.php:

$MEDIA = getID('media',false); // no cleaning - maybe external

with

$MEDIA = preg_replace('/[\x00-\x1F]+/s','',getID('media',false));

Resolution

All DokuWiki users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=www-apps/dokuwiki-20061106"