Vulnerabilities

Valve Steam before 2021-04-17, 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.

An issue was discovered in Valve Steam Client 2.10.91.91.

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.

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…

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 tha…

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.

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.

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.

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.