Multiple vulnerabilities in Mozilla Firefox before 1.5.0.5, Thunderbird before 1.5.0.5, and SeaMonkey before 1.0.3 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via Javascript that leads to memory corruption, including (1) nsListControlFrame::FireMenuItemActiveEvent, (2) buffer overflows in the string class in out-of-memory conditions, (3) table row and column groups, (4) "anonymous box selectors outside of UA stylesheets," (5) stale references to "removed nodes," and (6) running the crypto.generateCRMFRequest callback on deleted context.