# CVE-2025-67747: Fickling has missing detection for marshal.loads and types.FunctionType in unsafe modules list

> Attackers can bypass security checks in Fickling to execute arbitrary code via malicious pickle files due to missing module blocklist entries.

- **Severity:** High 7.1 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 16 Dec 2025
- **Also known as:** GHSA-565g-hwwr-4pp3, PYSEC-2026-1368

## What is CVE-2025-67747?

CVE-2025-67747 is a high-severity unsafe deserialization vulnerability in trailofbits fickling, published on 16 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Fickling is a Python pickling decompiler and static analyzer. Versions prior to 0.1.6 are missing `marshal` and `types` from the block list of unsafe module imports. Fickling started blocking both modules to address this issue. This allows an attacker to craft a malicious pickle file that can bypass fickling since it misses detections for `types.FunctionType` and `marshal.loads`. A user who deserializes such a file, believing it to be safe, would inadvertently execute arbitrary code on their system. This impacts any user or system that uses Fickling to vet pickle files for security issues. The issue was fixed in version 0.1.6.

Weakness: CWE-502 (Deserialization of Untrusted Data), CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2025-67747?

3 open source packages ship an affected version, including fickling. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fickling` | PyPI | All versions | 0.1.6 |
| `fickling` | PyPI | All versions | 0.1.6 |
| `fickling` | PyPI | All versions | 0.1.6 |

Products: Trailofbits Fickling.

## How do I fix CVE-2025-67747?

Upgrade fickling to 0.1.6 or later.

## Is CVE-2025-67747 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-67747 exists.

## Other vulnerabilities in trailofbits fickling

- [CVE-2026-22606](https://insights.sbomify.com/CVE-2026-22606/): Fickling has a bypass via runpy.run_path() and runpy.run_module() (high 8.9)
- [CVE-2026-22607](https://insights.sbomify.com/CVE-2026-22607/): Fickling Blocklist Bypass: cProfile.run() (high 8.9)
- [CVE-2026-22608](https://insights.sbomify.com/CVE-2026-22608/): Fickling vulnerable to use of ctypes and pydoc gadget chain to bypass detection (high 8.9)
- [CVE-2026-22609](https://insights.sbomify.com/CVE-2026-22609/): Fickling has Static Analysis Bypass via Incomplete Dangerous Module Blocklist (high 8.9)
- [CVE-2026-22612](https://insights.sbomify.com/CVE-2026-22612/): Fickling vulnerable to detection bypass due to "builtins" blindness (high 8.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-67747 and fix it if it is affected.

What it is: CVE-2025-67747 is a high-severity unsafe deserialization vulnerability in trailofbits fickling, published on 16 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-67747 exists.

Affected packages and fixed versions:
- fickling (PyPI): affected all versions; fixed in 0.1.6
- fickling (PyPI): affected all versions; fixed in 0.1.6
- fickling (PyPI): affected all versions; fixed in 0.1.6

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-2025-67747/ (Markdown: https://insights.sbomify.com/CVE-2025-67747/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-67747
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-67747
- OSV: https://osv.dev/vulnerability/CVE-2025-67747

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-67747/
Summaries are generated and may contain mistakes; the official description above is the record.