Valve's Source SDK (source-sdk-2013)'s ragdoll model parsing logic contains a stack-based buffer overflow vulnerability.The tokenizer function nexttoken copies characters from an input string into a fixed-size stack buffer without performing bounds checks. When ParseKeyValue processes a collisionpair rule longer than the destination buffer (256 bytes), an overflow of the stack buffer szToken can occur and overwrite the function return address. A remote attacker can trigger the vulnerable code by supplying a specially crafted ragdoll model which causes the oversized collisionpair rule to be parsed, resulting in remote code execution on affected clients or servers. Valve has addressed this issue in many of their Source games, but independently-developed games must manually apply patch.

An issue in Valvesoftware Steam Client Steam Client 1738026274 allows attackers to escalate privileges via a crafted executable or DLL.