CVE-2025-56005 – PLY 3.11 Arbitrary Code Execution

https://notcve.org/view.php?id=CVE-2025-56005

20 Jan 2026 — 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 activ... • https://packetstorm.news/files/id/214433 • CWE-502: Deserialization of Untrusted Data •