What’s Vulnerable › Vulnerabilities

CVE-2020-6016

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 6.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-11-18 · updated 2026-06-17
• Weakness: CWE-590

Description

Valve's Game Networking Sockets prior to version v1.2.0 improperly handles unreliable segments with negative offsets in function SNP_ReceiveUnreliableSegment(), leading to a Heap-Based Buffer Underflow and a free() of memory not from the heap, resulting in a memory corruption and probably even a remote code execution.

Affected products

• Game Networking Sockets: before 1.2.0 — fixed in 1.2.0

How to fix

Upgrade to a fixed version: Game Networking Sockets 1.2.0. Check the vendor advisory for mitigations.

References

• https://github.com/ValveSoftware/GameNetworkingSockets/commit/e0c86dcb9139771db3db0cfdb1fb8bef0af19c43
• https://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/
• https://github.com/ValveSoftware/GameNetworkingSockets/commit/e0c86dcb9139771db3db0cfdb1fb8bef0af19c43
• https://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/

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