CVE-2025-56005

CRITICAL

9.8

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.

CVE Details

CVSS v3.1 Score9.8

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/20/2026

Last Modified2/6/2026

Sourcenvd

Honeypot Sightings0

Affected Products

dabeaz:ply

Weaknesses (CWE)

CWE-502

References

https://github.com/bohmiiidd/Undocumented-RCE-in-PLY(cve@mitre.org)

https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005(cve@mitre.org)

https://github.com/tom025/ply_exploit_rejection(cve@mitre.org)

https://github.com/tom025/ply_exploit_rejection/issues/1(cve@mitre.org)

http://www.openwall.com/lists/oss-security/2026/01/23/4(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2026/01/23/5(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2026/01/28/5(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2026/01/29/1(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2026/01/29/2(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2026/01/30/1(af854a3a-2127-422b-91ae-364da2661108)

IOC Correlations

No correlations recorded

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