Hotfix: Unity Security Update for Cities: Skylines II


Cities: Skylines II artwork

Hello, Mayors!

We’ve released a hotfix to address security vulnerabilities found in the specific Unity runtime used by Cities: Skylines II. To review the full advisory and technical details, please see Unity’s security bulletin linked below.

Unity security advisory — September 2025

Note: these security issues do not affect the original Cities: Skylines (1); no update is required for that title.