CVE-2017-20205
Valve Source SDK Stack-Based Buffer Overflow RCE
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
9.2
Valve Source SDK Stack-Based Buffer Overflow RCE
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.
- Record
CVE-2017-20205- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-121
- Updated
- 2026-11-02
EUVDEUVD-2017-18920
9.2
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.
- Record
EUVD-2017-18920- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-g2mq-5mgx-wg6w
9.2
Valve's Source SDK (source-sdk-2013)'s ragdoll model parsing logic contains a stack-based buffer...
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.
- Record
GHSA-g2mq-5mgx-wg6w- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-121
- Updated
- 2026-11-02
NVD
9.2
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.
- Record
CVE-2017-20205- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-121
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2017-20205 is a critical vulnerability (CVSS 9.2) in Valve Software Source Sdk (source-sdk-2013), published October 15, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.69%, the 53rd percentile. No source names a fixed version.