picklescan before 0.0.22 only considers standard pickle file extensions in the scope for its vulnerability scan. An attacker could craft a malicious model that uses Pickle and include a malicious pickle file with a non-standard file extension. Because the malicious pickle file inclusion is not considered as part of the scope of picklescan, the file would pass security checks and appear to be safe, when it could instead prove to be problematic.
picklescan before 0.0.21 does not treat 'pip' as an unsafe global. An attacker could craft a malicious model that uses Pickle to pull in a malicious PyPI package (hosted, for example, on pypi.org or GitHub) via `pip.main()`. Because pip is not a restricted global, the model, when scanned with picklescan, would pass security checks and appear to be safe, when it could instead prove to be problematic.