mailnews in Mozilla Thunderbird before 2.0.0.18 and SeaMonkey before 1.1.13, when JavaScript is enabled in mail, allows remote attackers to obtain sensitive information about the recipient, or comments in forwarded mail, via script that reads the (1) .documentURI or (2) .textContent DOM properties.
https://exchange.xforce.ibmcloud.com/vulnerabilities/46734
https://bugzilla.mozilla.org/show_bug.cgi?id=458883
http://www.securitytracker.com/id?1021247
http://www.securityfocus.com/bid/32363
http://www.mozilla.org/security/announce/2008/mfsa2008-59.html