# 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.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Jan 2026
- **Updated:** 17 Sep 2026
- **Also known as:** DEBIAN-CVE-2025-56005, GHSA-qc6m-pwr3-g72p, MGASA-2026-0079, OESA-2026-1481, OESA-2026-1594, OESA-2026-1595, OESA-2026-1596, OESA-2026-1597, UBUNTU-CVE-2025-56005, openSUSE-SU-2026:10418-1

## 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 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2025-56005?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `python-jsonpath-ng` | openSUSE:Tumbleweed | All versions | 1.8.0-1.1 |

Products: Dabeaz Ply.

## How do I fix CVE-2025-56005?

No fix published yet.

## 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:

- Arguments to reject CVE-2025-56005 (github_poc): https://github.com/tom025/ply_exploit_rejection
- This is a modified version of PLY 3.11, from PyPI (current defunct git repo is not current to PyPI) which reimplements the pickle function in yacc.py to resolve CVE-2025-56005. (github_poc): https://github.com/gdfurr98/ply-safepickle
- Lab demonstrating that CVE-2025-56005 is real and does allow arbitrary code execution at a minimum (the debate about RCE notwithstanding here), and shows that ply-safepickle does block the exploit path. (github_poc): https://github.com/gdfurr98/ply-cve-2025-56005-lab

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-56005 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-56005 exists.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-56005/ (Markdown: https://insights.sbomify.com/CVE-2025-56005/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-56005
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-56005
- OSV: https://osv.dev/vulnerability/CVE-2025-56005

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-56005/
Summaries are generated and may contain mistakes; the official description above is the record.