Elevated Privilege via Incorrect Use of Privileged APIs in Unity Parsec on Windows

An Incorrect Use of Privileged APIs vulnerability in Unity Parsec on Windows hosts leads to a potential Elevation of Privilege. This issue affects Parsec through v2026-05-04.0. The patched version is Parsec for Windows version 150-104a. A user can generate a situation where there is an instance of parsecd.exe running as NT AUTHORITY\SYSTEM with a user-controlled value of the AppData environment variable.

Unity Runtime before 2025-10-02 on Android, Windows, macOS, and Linux allows argument injection that can result in loading of library code from an unintended location. If an application was built with a version of Unity Editor that had the vulnerable Unity Runtime code, then an adversary may be able to execute code on, and exfiltrate confidential information from, the machine on which that application is running. NOTE: product status is provided for Unity Editor because that is the information available from the Supplier. However, updating Unity Editor typically does not address the effects of the vulnerability; instead, it is necessary to rebuild and redeploy all affected applications.

Unity Parsec has a TOCTOU race condition that permits local attackers to escalate privileges to SYSTEM if Parsec was installed in "Per User" mode. The application intentionally launches DLLs from a user-owned directory but intended to always perform integrity verification of those DLLs. This affects Parsec Loader versions through 8. Parsec Loader 9 is a fixed version.

The Unity Web Player plugin before 4.6.6f2 and 5.x before 5.0.3f2 allows attackers to read messages or access online services via a victim's credentials