Frei0r

How heap buffer overflow via strcpy() happens in C frei0r plugins and how to fix it

A critical heap buffer overflow vulnerability was discovered in the frei0r video plugin `cairoaffineblend.c`, where `strcpy()` was used to copy user-controlled blend mode strings without any bounds checking. An attacker controlling plugin parameters could overflow the heap buffer, corrupt adjacent memory, and potentially achieve arbitrary code execution. The fix replaces `strcpy()` with bounded `memcpy()` operations and adds proper `realloc()` error handling.