What if you have an old flash player?

What could outdated version of flash player cause? I am myself a safe browser, i never open malicious sites. But I am using an old flash player due to my flash player problems with this computer (i guess a register issue). But I am not planning on fixing it since as far as I have heard there is no need for latest version as far as you are being safe and aware. Also, could the game that requires flash player somehow be a risk? Could the developer that wrote the game in flash code somehow see that i am using an older version of flash player and try to use this vulnerability of flash player against me?