cvedb.io
CVE-2025-56005
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2026-01-20T19:15:49.247 · Last modified 2026-06-30T03:16:52.847

Summary

An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the `picklefile` parameter in the `yacc()` function. This parameter accepts a `.pkl` file that is deserialized with `pickle.load()` without validation. Because `pickle` allows execution of embedded code via `__reduce__()`, an attacker can achieve code execution by passing a malicious pickle file. The parameter is not mentioned in official documentation or the GitHub repository, yet it is active in the PyPI version. This introduces a stealthy backdoor and persistence risk. NOTE: A third-party states that this vulnerability should be rejected because the proof of concept does not demonstrate arbitrary code execution and fails to complete successfully.

Affected products

dabeaz — ply

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.