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Vulnerability record · CVE-2020-6017 · published 3 December 2020

CVE-2020-6017: Valvesoftware game networking sockets classic buffer overflow vulnerability

Valvesoftware · Game Networking Sockets

Valve's Game Networking Sockets prior to version v1.2.0 improperly handles long unreliable segments in function SNP_ReceiveUnreliableSegment() when configured to support plain-text messages, leading to a Heap-Based Buffer Overflow and resulting in a memory corruption and possibly even a remote code execution.

9.8 CVSS 3.1 Critical EPSS 3.2% · top 12.2% CWE-120 · Classic buffer overflowCWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score, v2 7.5
3.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

Valve's Game Networking Sockets prior to version v1.2.0 improperly handles long unreliable segments in function SNP_ReceiveUnreliableSegment() when configured to support plain-text messages, leading to a Heap-Based Buffer Overflow and resulting in a memory corruption and possibly even a remote code execution.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/ValveSoftware/GameNetworkingSockets/commit/e0c86dcb9139771db3db0cfdb1fb8bef0af19c43 PatchThird Party Advisory
https://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/ ExploitThird Party Advisory
https://github.com/ValveSoftware/GameNetworkingSockets/commit/e0c86dcb9139771db3db0cfdb1fb8bef0af19c43 PatchThird Party Advisory
https://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/ ExploitThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2020-6017), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.