CVE 2009-0357

Mozilla Firefox before 3.0.6 and SeaMonkey before 1.1.15 do not properly restrict access from web pages to the (1) Set-Cookie and (2) Set-Cookie2 HTTP response headers, which allows remote attackers to obtain sensitive information from cookies via XMLHttpRequest calls, related to the HTTPOnly protection mechanism.

See the CVE page on Mitre.org for more details.