CVE-2025-67747: trailofbits fickling · Incomplete List of Disallowed Inputs
Affects trailofbits ficklingSource CVE Database V5
Public exploit available · CVSS 7.1 High : upgrade to 0.1.6 as a priority.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.1.6
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:PExploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade trailofbits fickling to 0.1.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
PyPIficklingpkg:pypi/ficklingOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
- Immediately upgrade Fickling to version 0.1.6 or later to ensure the block list includes 'marshal' and 'types' modules.
- Implement strict controls on the sources of pickle files, ensuring only trusted and verified data is deserialized.
- Employ defense-in-depth by combining static analysis tools like Fickling with runtime protections such as sandboxing or containerization when processing pickle files.
- Educate developers and security teams about the risks of deserializing untrusted pickle data and the importance of using updated analysis tools.
- Monitor systems for unusual activity that could indicate exploitation attempts, especially around processes handling pickle files.
- Consider alternative serialization formats that are safer than pickle, such as JSON or protobuf, where feasible.
- Review and harden CI/CD pipelines and automated workflows to prevent deployment of malicious pickle files.
- Conduct regular security audits and vulnerability assessments focusing on deserialization components in Python applications.
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.
References
- github.com/trailofbits/fickling/security/advisories/GHSA-565g-hwwr-4pp3 (opens in a new tab)
- github.com/trailofbits/fickling/pull/186 (opens in a new tab)
- github.com/trailofbits/fickling/commit/4e34561301bda1450268d1d7b0b2b151de33b913 (opens in a new tab)
- github.com/trailofbits/fickling/releases/tag/v0.1.6 (opens in a new tab)