Multiple unspecified vulnerabilities in the JavaScript engine in Mozilla Firefox before 3.0.14 and 3.5.x before 3.5.2, Thunderbird before 2.0.0.24, and SeaMonkey before 1.1.19 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via vectors related to use of mutable strings in the js_StringReplaceHelper function in js/src/jsstr.cpp, and unknown vectors.