Drupal 5.x before 5.13 and 6.x before 6.7 does not delete all related content when an input format is deleted, which prevents the content from being properly filtered and allows remote attackers to conduct cross-site scripting (XSS) attacks via unspecified vectors.
https://www.redhat.com/archives/fedora-package-announce/2008-December/msg00767.html
https://www.redhat.com/archives/fedora-package-announce/2008-December/msg00740.html
https://exchange.xforce.ibmcloud.com/vulnerabilities/47259
http://www.vupen.com/english/advisories/2008/3414
http://secunia.com/advisories/33147