No product is perfect. While UC Browser Portable sits at the of the portability list, consider these caveats:
Found to use outdated RC4 ciphers and SSL 3.0/2.0 protocols, making it susceptible to exploits like Logjam, FREAK, and POODLE . uc browser portable top
Past reports have flagged vulnerabilities where unencrypted sensitive data (like geolocation and Wi-Fi data) were leaked to remote servers. Availability No product is perfect