CVE-2025-56005 Deserialization in n/a
An undocumented feature in the PLY library allows remote code execution via unsafe deserialization of pickle files passed to the yacc function.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-56005?
CVE-2025-56005 is a critical unsafe deserialization vulnerability in n/a, published on 20 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-502
Which versions are affected by CVE-2025-56005?
It affects 1 product.
Linux distribution packages (1)
python-jsonpath-ng openSUSE:Tumbleweed | All versions | 1.8.0-1.1 |
Products include Dabeaz Ply.
How do I fix CVE-2025-56005?
No fix published yet.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-56005 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-56005 exists.
Public exploit code: 3 proofs of concept on GitHub.
Sources
Also known as DEBIAN-CVE-2025-56005, GHSA-qc6m-pwr3-g72p, MGASA-2026-0079, OESA-2026-1481, OESA-2026-1594, OESA-2026-1595 and 4 more.