disputed

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.

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.

https://github.com/tom025/ply_exploit_rejection/issues/1

http://www.openwall.com/lists/oss-security/2026/01/30/1

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

CVE: http://www.openwall.com/lists/oss-security/2026/01/23/4 Types: Exploit, Mailing List

CVE: http://www.openwall.com/lists/oss-security/2026/01/23/5 Types: Mailing List

CVE: http://www.openwall.com/lists/oss-security/2026/01/28/5 Types: Exploit, Mailing List

CVE: http://www.openwall.com/lists/oss-security/2026/01/29/1 Types: Exploit, Mailing List

CVE: http://www.openwall.com/lists/oss-security/2026/01/29/2 Types: Mailing List

MITRE: https://github.com/bohmiiidd/Undocumented-RCE-in-PLY Types: Exploit, Third Party Advisory

MITRE: https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005 Types: Exploit, Third Party Advisory

MITRE: https://github.com/tom025/ply_exploit_rejection Types: Exploit, Mitigation, Third Party Advisory

http://www.openwall.com/lists/oss-security/2026/01/29/2

http://www.openwall.com/lists/oss-security/2026/01/29/1

http://www.openwall.com/lists/oss-security/2026/01/28/5

https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005

https://github.com/tom025/ply_exploit_rejection

http://www.openwall.com/lists/oss-security/2026/01/23/5

http://www.openwall.com/lists/oss-security/2026/01/23/4

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

CWE-502

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.

https://github.com/bohmiiidd/Undocumented-RCE-in-PLY