CVE-2025-71359 picklescan CVE debrief

Who should care

Developers and users of picklescan before version 0.0.29 should be aware of this vulnerability. As the vendor and product information is not clearly identified, users of picklescan in general should take precautions. This vulnerability could allow attackers to execute remote code, potentially leading to system compromise.

Technical summary

The vulnerability exists in the picklescan library before version 0.0.29. Specifically, it fails to detect malicious pickle payloads that use the lib2to3.pgen2.grammar.Grammar.loads method in the reduce function. This allows attackers to craft malicious pickle files that can execute arbitrary code when deserialized using pickle.load(). The vulnerability is exacerbated by the fact that picklescan is designed to scan pickle files for malicious content, but in this case, it fails to identify dangerous payloads. The Common Weakness Enumeration (CWE) associated with this vulnerability is CWE-502, which involves the deserialization of untrusted data.

Defensive priority

High priority should be given to updating picklescan to version 0.0.29 or later. In the meantime, users should exercise caution when deserializing pickle files from untrusted sources.

Recommended defensive actions

• Update picklescan to version 0.0.29 or later.
• Validate and sanitize all pickle files before deserialization.
• Use secure protocols for transferring pickle files.
• Monitor systems for suspicious activity related to pickle file deserialization.
• Consider implementing additional security controls, such as using alternative serialization formats.

Evidence notes

The evidence for this CVE comes from the NVD and Vulncheck. The CVE was published on July 4, 2026. The vulnerability details were provided by Vulncheck, which identified the issue in picklescan. The CVE record and NVD detail pages provide additional context and technical information about the vulnerability.

Official resources