Tango discovered that ikiwiki, a wiki compiler, is not validating if the htmlscrubber plugin is enabled or not on a page when adding alternative stylesheets to pages. This enables an attacker who is able to upload custom stylesheets to add malicious stylesheets as an alternate stylesheet, or replace the default stylesheet, and thus conduct cross-site scripting attacks. The oldstable distribution , this problem has been fixed in version 2.53.6.