CVE-2020-15530

Name: CVE-2020-15530
Creator: NVD / NIST
Published: 2020-07-05T01:15:10.79+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.49%

Last modified Jun 17, 2026

CVE-2020-15530 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.49% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.49%

38.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-362

Affected Software

Vendor	Product	Versions
Valvesoftware	Steam Client	2.10.91.91

References

http://daniels-it-blog.blogspot.com/2020/07/steam-arbitrary-code-execution-part-2.htmlExploit, Third Party Advisory
http://daniels-it-blog.blogspot.com/2020/07/steam-arbitrary-code-execution-part-2.htmlExploit, Third Party Advisory

Timeline

Published: Jul 5, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15530?

How severe is CVE-2020-15530?

CVE-2020-15530 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.49% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15530?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-15530?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST