zlacker

>They specifically went to the third-party vendor, because the third-party vendor offers a platform to give them credit and pay them for finding security exploits. It is not the responsibility of the third-party vendor to manage all bug reports.

I don't know, the wording on their site suggests hackerone is the primary place to report security issues, not "if you want to get paid use hackerone, otherwise email us directly".

>For issues with Steam or with Valve hardware products, please visit HackerOne — https://hackerone.com/valve. Our guidelines for responsible disclosure are also available through that program.

https://www.valvesoftware.com/en/security