Running the attached swf file in Google Chrome (Linux x64) will eventually result in dialog offering to terminate the slow script. (Not the Google Chrome infobar that says that Flash isn't responding, but the dialog that appears after that.)
Upon electing to terminate the script, a crash occurs.
It is not known whether this bug can be triggered or not without user interaction.
The crashing swf is signal_sigsegv_7ffff5ce5ea4_6963_b1d6342468487426c7ea26c725453e7d.swf
The base file from which the mutated file was generated is b1d6342468487426c7ea26c725453e7d.swf
On Linux x64, the crash looks like this:
=> 0x00007f6931525318: andl $0xffffffbf,0x3c(%rax)
rax 0x7ff8000000000000 9221120237041090560
And if we look back in the assembly a bit, the wild value has come from %rbx that points to a block of wild values.
Proof of Concept: