picklescan before 0.0.30 fails to detect malicious pickle files that employ the idlelib.pyshell.ModifiedInterpreter.runcommand method within reduce functions, allowing an attacker to embed code that is executed when the file is deserialized. The flaw is a deserialization vulnerability (CWE-502) that results in arbitrary code execution, potentially granting full control over the system running picklescan.

All instances of picklescan:picklescan with versions earlier than 0.0.30 are affected. The vulnerability is exposed whenever the application processes pickle files using its reduce methods.

The CVSS score of 7.6 classifies this flaw as high severity. No EPSS score is available and the issue is not listed in the CISA KEV catalog, but the absence of mitigations means an attacker who can supply a malicious pickle file to the application can gain arbitrary execution. Based on the description, the attacker must supply a malicious pickle file that the victim deserializes, which can occur locally or via network input depending on how picklescan is used. Once executed, the code runs with the privileges of the picklescan process, posing a significant risk to confidentiality, integrity, and availability.