CVE-2025-56005
Dabeaz Ply
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.
Exploitation status
- Published references include exploit or proof-of-concept material. There is no confirmation it is being used in real attacks.
What the metrics mean
- It is reachable over a network, without needing local access.
- For an attacker who can reach it, no special conditions are needed to exploit it.
- To exploit it, no account is needed.
- Beyond that, no action by a user is required.
Scoring
- CVSS
- 9.8 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness
- CWE-502
- Assigned by
- cve@mitre.org
Dates
- Published
- 2026-01-20
- Last modified
- 2026-08-24
- Sources
- NVD
Affected products
- Dabeaz Ply3.11
As listed in the NVD configuration data. Not a statement about your estate.
References
- https://github.com/bohmiiidd/Undocumented-RCE-in-PLY
- https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005
- https://github.com/tom025/ply_exploit_rejection
- https://github.com/tom025/ply_exploit_rejection/issues/1
- http://www.openwall.com/lists/oss-security/2026/01/23/4
- http://www.openwall.com/lists/oss-security/2026/01/23/5
- http://www.openwall.com/lists/oss-security/2026/01/28/5
- http://www.openwall.com/lists/oss-security/2026/01/29/1
- http://www.openwall.com/lists/oss-security/2026/01/29/2
- http://www.openwall.com/lists/oss-security/2026/01/30/1
- https://access.redhat.com/security/cve/CVE-2025-56005
- https://bugzilla.redhat.com/show_bug.cgi?id=2431308
- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-56005.json