CVE-2020-15530

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-07-05 · updated 2026-06-17
Weakness: CWE-362

Description

An issue was discovered in Valve Steam Client 2.10.91.91. The installer allows local users to gain NT AUTHORITY\SYSTEM privileges because some parts of %PROGRAMFILES(X86)%\Steam and/or %COMMONPROGRAMFILES(X86)%\Steam have weak permissions during a critical time window. An attacker can make this time window arbitrarily long by using opportunistic locks.

Affected products

Valvesoftware Steam Client: 2.10.91.91

References

http://daniels-it-blog.blogspot.com/2020/07/steam-arbitrary-code-execution-part-2.html
http://daniels-it-blog.blogspot.com/2020/07/steam-arbitrary-code-execution-part-2.html

Get alerted when CVE-2020-15530 or the next vulnerability affects your stack