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.
- 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
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.
Which versions are affected by CVE-2025-67747?
3 open source packages ship an affected version, including fickling. It affects 1 product.
| Package | 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 include Trailofbits Fickling.
How do I fix CVE-2025-67747?
Upgrade fickling to 0.1.6 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
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 Fickling has a bypass via runpy.run_path() and runpy.run_module()
- CVE-2026-22607 Fickling Blocklist Bypass: cProfile.run()
- CVE-2026-22608 Fickling vulnerable to use of ctypes and pydoc gadget chain to bypass detection
- CVE-2026-22609 Fickling has Static Analysis Bypass via Incomplete Dangerous Module Blocklist
- CVE-2026-22612 Fickling vulnerable to detection bypass due to "builtins" blindness
Sources
Also known as GHSA-565g-hwwr-4pp3, PYSEC-2026-1368.