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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/bohmiiidd/Undocumented-RCE-in-PLY	Exploit Third Party Advisory
https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005	Exploit Third Party Advisory
https://github.com/tom025/ply_exploit_rejection	Exploit Mitigation Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/01/23/4	Exploit Mailing List
http://www.openwall.com/lists/oss-security/2026/01/23/5	Mailing List
http://www.openwall.com/lists/oss-security/2026/01/28/5	Exploit Mailing List
http://www.openwall.com/lists/oss-security/2026/01/29/1	Exploit Mailing List
http://www.openwall.com/lists/oss-security/2026/01/29/2	Mailing List
http://www.openwall.com/lists/oss-security/2026/01/30/1

Configurations

Configuration 1 (hide)

cpe:2.3:a:dabeaz:ply:3.11:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-01-20 19:15

Updated : 2026-01-30 23:16

NVD link : CVE-2025-56005

Mitre link : CVE-2025-56005

CVE.ORG link : CVE-2025-56005

JSON object : View

Products Affected

dabeaz

ply

CWE

CWE-502

Deserialization of Untrusted Data

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