Cyber Resilience

CVE-2025-67747

Deserialization in Trailofbits Fickling ≤ 0.1.6

Public PoCDeserialization
Published
16 December 2025
Modified
02 January 2026
Patch / advisory
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS: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:X/V:X/RE:X/U:X
EPSS Score 0.0025 17th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2025-67747 is a high-severity Incomplete List of Disallowed Inputs (CWE-184) vulnerability in Trailofbits Fickling. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-22607Same product: Trailofbits Fickling
CVE-2026-22606Same product: Trailofbits Fickling
CVE-2026-14534Same product: Trailofbits Fickling
CVE-2026-22609Same product: Trailofbits Fickling
CVE-2026-22608Same product: Trailofbits Fickling
CVE-2026-22612Same product: Trailofbits Fickling
CVE-2025-67748Same product: Trailofbits Fickling
CVE-2026-14535Same product: Trailofbits Fickling
CVE-2026-54512Shared CWE-184, CWE-502
CVE-2024-3301Shared CWE-502

Affected Assets

trailofbits
fickling
≤ 0.1.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V3.5.2
  • V4.4.2
  • V16.2.5

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can uncover deserialization flaws before deployment.

SI-10 requires validity checks on inputs, which structurally replaces incomplete deny-lists with complete allow-list or sanitization logic.

Engineering principles such as safe deserialization and input sanitization structurally prevent the weakness from being introduced.

Integrity verification tools can detect malformed or tampered serialized data after the fact.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require complete, positive input validation instead of incomplete denylists.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can discover missing input checks, but does not prevent the weakness during development.

prevents

Application security requirements can mandate complete input validation rules, but the control itself does not prescribe how to build those rules.

prevents

Secure architecture principles include robust input validation design, yet the control is broader than this single weakness.

prevents

Secure coding standards directly require exhaustive allow-lists or complete deny-lists for inputs, addressing the root cause of incomplete disallowed-input lists.

finds

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References