Steam Client Security Vulnerabilities

CVE-2015-4016

The client detection protocol in Valve Steam allows remote attackers to cause a denial of service (process crash) via a crafted response to a broadcast packet.

CVE-2015-7985

Valve Steam 2.10.91.91 uses weak permissions (Users: read and write) for the Install folder, which allows local users to gain privileges via a Trojan horse steam.exe file.

CVE-2018-12270

In Valve Steam 1528829181 BETA, it is possible to perform a homograph / homoglyph attack to create fake URLs in the client, which may trick users into visiting unintended web sites.

CVE-2019-14743

In Valve Steam Client for Windows through 2019-08-07, HKLM\SOFTWARE\Wow6432Node\Valve\Steam has explicit "Full control" for the Users group, which allows local users to gain NT AUTHORITY\SYSTEM access.

CVE-2019-15315

Valve Steam Client for Windows through 2019-08-16 allows privilege escalation (to NT AUTHORITY\SYSTEM) because local users can replace the current versions of SteamService.exe and SteamService.dll with older versions that lack the CVE-2019-14743 patch.

CVE-2019-15316

Valve Steam Client for Windows through 2019-08-20 has weak folder permissions, leading to privilege escalation (to NT AUTHORITY\SYSTEM) via crafted use of CreateMountPoint.exe and SetOpLock.exe to leverage a TOCTOU race condition.

CVE-2019-17180

Valve Steam Client before 2019-09-12 allows placing or appending partially controlled filesystem content, as demonstrated by file modifications on Windows in the context of NT AUTHORITY\SYSTEM. This could lead to denial of service, elevation of privilege, or unspecified other impact.

CVE-2020-15530

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 tim...

CVE-2021-24476

The Steam Group Viewer WordPress plugin through 2.1 does not sanitise or escape its "Steam Group Address" settings before outputting it in the page, leading to an authenticated Stored Cross-Site Scripting issue

CVE-2021-30481

Valve Steam through 2021-04-10, when a Source engine game is installed, allows remote authenticated users to execute arbitrary code because of a buffer overflow that occurs for a Steam invite after one click.