Firefox before 1.0.3 and Mozilla Suite before 1.7.7, when blocking a popup, allows remote attackers to execute arbitrary code via a javascript: URL that is executed when the user selects the "Show javascript" option.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9584
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A100023
https://bugzilla.mozilla.org/show_bug.cgi?id=289204
http://www.securityfocus.com/bid/15495
http://www.redhat.com/support/errata/RHSA-2005-386.html
http://www.redhat.com/support/errata/RHSA-2005-384.html
http://www.redhat.com/support/errata/RHSA-2005-383.html
http://www.mozilla.org/security/announce/mfsa2005-35.html
http://www.gentoo.org/security/en/glsa/glsa-200504-18.xml