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Vulnerability record · CVE-2025-67747 · published 16 December 2025

CVE-2025-67747: Trailofbits fickling deserialization of untrusted data vulnerability

Trailofbits · Fickling

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.

7.1 CVSS 4.0 High EPSS 0.28% · top 81.8% CWE-184 · CWE-184CWE-502 · Deserialization of untrusted data
7.1CVSS 4.0 base score
0.28%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 1 tagged exploit
17 Jun 2026Last modified by NVD

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.

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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/trailofbits/fickling/commit/4e34561301bda1450268d1d7b0b2b151de33b913 Patch
https://github.com/trailofbits/fickling/pull/186 Issue Tracking
https://github.com/trailofbits/fickling/releases/tag/v0.1.6 Release Notes
https://github.com/trailofbits/fickling/security/advisories/GHSA-565g-hwwr-4pp3 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-67747), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.