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Fencer Vulns
critical 9.8

CVE-2020-6017 json

Valve's Game Networking Sockets prior to version v1.2.0 improperly handles long unreliable segments in function SNP_ReceiveUnreliableSegmen…

published 2020-12-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-27171

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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.

Patch / fix

  • valvesoftware game_networking_sockets 1.2.0

Exploit prediction

3.23% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • research.checkpoint.com https://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a Game Networking Sockets

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.