F00F, FDIV, COMA (look these up on the wikipedia)... there have been lots of bugs in various cpus over the years... each possible to cause a freeze or crash but ive never heard of one that lets someone remotely inject asm and run it... ...but my gut says the OSes will eventually be patched for the new bug(s?) like they have for the others...
EDIT:
The proof-of-concept attacks will show how processor bugs, called errata, can be exploited using certain instruction sequences and a knowledge of how Java compilers work, allowing an attacker to take control of the compiler.
(emphasis mine)
theres how they are getting around the variances in operating systems.... using the environment of Java's JIT compiler (which is basically an OS in of itself)... i knew the 'OS independant' thing seemed a bit fishy...