Vulnerability descriptio from the Unity website:
"Applications that were built using affected versions of the Unity Editor are susceptible to an unsafe file loading and local file inclusion attack depending on the operating system, which could enable local code execution or information disclosure at the privilege level of the vulnerable application. There is no evidence of any exploitation of the vulnerability nor has there been any impact on users or customers. Unity has provided fixes that address the vulnerability and they are already available to all developers."
For more information, you can check Unity's patch notes on: https://unity.com/es/security/sept-2025-01