Regarding today's reported leak of code, specifically as it pertains to TF2: This also appears to be related to code depots released to partners in late 2017, and originally leaked in 2018.

From our review, we have not found any reason for TF2 players to be alarmed or avoid the current builds (as always, playing on the official servers is recommended for greatest security).

We will continue to investigate the situation and will update news outlets and players if we find anything to prove otherwise. In the meantime, if anyone has more information about the leak, the Valve security page (next tweet) describes how best to report that information.

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