CRLF injection vulnerability in the nsCookieService::SetCookieStringInternal function in netwerk/cookie/nsCookieService.cpp in Mozilla Firefox before 3.6.18 and 4.x through 4.0.1, and Thunderbird before 3.1.11, allows remote attackers to bypass intended access restrictions via a string containing a \n (newline) character, which is not properly handled in a JavaScript "document.cookie =" expression, a different vulnerability than CVE-2011-2374.