MOD APKs do not receive official security patches from Piriform/Avast, meaning any newly discovered vulnerabilities will remain unpatched on your device . Community Perspectives
“CCleaner is not even moderately safe in general and has been marked as “PUA” Threat under Microsoft guidelines.” Quora CCleaner MOD APK 6.8.0 (Professional Unlocked) ...
Downloading a "MOD APK" from third-party sites is generally considered unsafe for several reasons: MOD APKs do not receive official security patches