Vulnerability · Published Dec 16, 2025 · Assigned by GitHub_M
CVE-2025-67747Fickling has missing detection for marshal.loads and types.FunctionType in unsafe modules list
High 7.1
In plain English
A high-severity unsafe deserialization in fickling from trailofbits. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | fickling | 0.1.6 | GHSA-565g-hwwr-4pp3 |
| PyPI | fickling | 0.1.6 | PYSEC-2026-1368 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| trailofbits | fickling | < 0.1.6 |
Weakness: CWE-184, CWE-502 · 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
References
- https://github.com/trailofbits/fickling/security/advisories/GHSA-565g-hwwr-4pp3 x_refsource_CONFIRM
- https://github.com/trailofbits/fickling/pull/186 x_refsource_MISC
- https://github.com/trailofbits/fickling/commit/4e34561301bda1450268d1d7b0b2b151de33b913 x_refsource_MISC
- https://github.com/trailofbits/fickling/releases/tag/v0.1.6 x_refsource_MISC