CVE-2025-56005

Critical · CVSS 9.8

PLY (Python Lex-Yacc) — Insecure Deserialization / Remote Code Execution via pickle.load()

CVSS: 9.8; nvd
EPSS: 16.9%; 97th pct
KEV: No
Class: oss containerizable; CWE-502, CWE-502

Description

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.

Search profile — drives PoC discovery

Symbols picklefileyacc()pickle.load()__reduce__ply.yaccpicklefile parameter

Keywords CVE-2025-56005PLY Python Lex-Yacc RCEpicklefile deserializationply yacc pickle exploitPLY 3.11 RCEply yacc picklefile backdoorpickle load RCE PLYbohmiiidd Undocumented-RCE-in-PLYply exploit rejectionCWE-502 PLY deserialization

Versions: 3.11

Ranked PoCs (2) — best first

Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.

bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005 needs review

cited in references · recent activity

gh_search

★ 0
tom025/ply_exploit_rejection needs review

cited in references · recent activity

gh_search · Python

★ 0

Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.

References

Status: enriched · ingested 2026-06-30T06:00:22.000Z · profiled 2026-06-30T18:30:14.000Z