CVE-2017-20205Network attack vector

Remote code execution via unchecked collisionpair token

Published Oct 15, 2025 · Updated Oct 15, 2025

Stack-based buffer overflow in Valve Source SDK 2013 allows remote attackers to execute code through a crafted ragdoll model. CRagdollCollisionRulesParse::ParseKeyValue passes an oversized collisionpair value to nexttoken, which copies it into the 256-byte stack buffer szToken without a length check. Loading attacker-supplied model data on an affected client or server can overwrite the return address and execute code in the game process.

CVSS severity9.2
Critical
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Valve Source SDK 2013 allows remote attackers to execute code through a crafted ragdoll model. CRagdollCollisionRulesParse::ParseKeyValue passes an oversized collisionpair value to nexttoken, which copies it into the 256-byte stack buffer szToken without a length check. Loading attacker-supplied model data on an affected client or server can overwrite the return address and execute code in the game process.

The record

CVE
CVE-2017-20205
Published
Oct 15, 2025
Updated
Oct 15, 2025
Vendor
Valve Corporation
Product
Source SDK 2013
Classifications
CWE-121, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=source-sdk-2013

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Valve Corporation · Source SDK 2013version=source-sdk-2013

Published CVSS scores

9.2VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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