[erglkjahlkh]

Buffer overflows are basically about memory corruption. They can lead to crashes, remote code execution, if run in privileged code to privilege escalation, etc.

Most modern operating systems have buffer overflow protection technologies such as ASLR. I tried recently exploiting a few guaranteed buffer overflows for fun, and it's getting irritatingly hard at least on Linux. Non-executable stack, *alloc functions have sanity checks, -fstack-protector provided canaries, ... It's possible to get past all that, but it takes a bit work.

I would be freaked if I was running some older operating system, and someone vendored a poorly compiled version of libpng. Windows applications are probably the scariest here, especially when run on older Windows servers...