CVE-2025-56005
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.
- CVSS v3.1 CNA
- 7.8 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS v3.1 CNA
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 18.81% chance of exploitation in the next 30 days, 97th percentile
- Published
- 2026-01-20
- Updated
- 2026-09-17
Proof-of-concept exploits (3)
- tom025/ply_exploit_rejection0★ · 2026-01-27
- gdfurr98/ply-cve-2025-56005-lab0★ · 2026-09-27
- gdfurr98/ply-safepickle0★ · 2026-09-27