CVE-2026-14534
Fickling check_safety() bypass via unlisted standard library modules (_posixsubprocess, site, atexit)
Description
Trail of Bits fickling versions up to and including 0.1.10 do not include the Python standard library modules _posixsubprocess, site, and atexit in the UNSAFE_IMPORTS denylist (fickle.py). Because these modules are absent from the denylist, fickling's check_safety() function returns LIKELY_SAFE with zero findings for pickle payloads that invoke dangerous functions including _posixsubprocess.fork_exec (C-level process spawner capable of executing arbitrary binaries), site.execsitecustomize (executes arbitrary site customization code), and atexit._run_exitfuncs (triggers all registered exit handler callbacks). The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate; a LIKELY_SAFE verdict causes the payload to be deserialized and executed. This shares the same root cause as CVE-2026-22607 (cProfile), CVE-2025-67748 (pty), and CVE-2025-67747 (marshal/types). OvertlyBadEvals does not flag these modules because they are standard library imports. UnsafeImports does not flag them because they are not in the denylist. The UnusedVariables heuristic is defeated by the SETITEMS opcode pattern.
INFO
Published Date :
July 4, 2026, 2:16 p.m.
Last Modified :
Oct. 25, 2026, 3:10 p.m.
Remotely Exploit :
Yes !
Source :
aa17e1a1-c329-4d6e-a1ed-8d0188aea082
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | aa17e1a1-c329-4d6e-a1ed-8d0188aea082 |
Solution
- Update fickling to version 0.1.11 or later.
- Ensure UNSAFE_IMPORTS includes critical modules.
- Avoid deserializing untrusted data.
- Review security configurations for imported modules.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-14534.
| URL | Resource |
|---|---|
| https://github.com/trailofbits/fickling/commit/e8408615b63adf034f891f653692ab9b51f0f5af | Patch |
| https://github.com/trailofbits/fickling/pull/272 | Issue Tracking Patch |
| https://github.com/trailofbits/fickling/releases/tag/v0.1.11 | Release Notes |
| https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697 | Exploit Vendor Advisory |
| https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-14534 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-14534
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-14534 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-14534 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: fickling de trailofbits, Description: Las versiones de fickling de Trail of Bits hasta la 0.1.10 inclusive no incluyen los módulos de la biblioteca estándar de Python _posixsubprocess, site y atexit en la lista de denegación UNSAFE_IMPORTS (fickle.py). Debido a que estos módulos están ausentes de la lista de denegación, la función check_safety() de fickling devuelve LIKELY_SAFE con cero hallazgos para cargas útiles de pickle que invocan funciones peligrosas, incluyendo _posixsubprocess.fork_exec (generador de procesos a nivel de C capaz de ejecutar binarios arbitrarios), site.execsitecustomize (ejecuta código de personalización de sitio arbitrario) y atexit._run_exitfuncs (activa todas las devoluciones de llamada de los gestores de salida registrados). La API fickling.load() encadena check_safety() en pickle.loads() como una puerta de seguridad explícita; un veredicto LIKELY_SAFE hace que la carga útil sea deserializada y ejecutada. Esto comparte la misma causa raíz que CVE-2026-22607 (cProfile), CVE-2025-67748 (pty) y CVE-2025-67747 (marshal/types). OvertlyBadEvals no marca estos módulos porque son importaciones de la biblioteca estándar. UnsafeImports no los marca porque no están en la lista de denegación. La heurística UnusedVariables es eludida por el patrón de código de operación SETITEMS. -
Initial Analysis by [email protected]
Jul. 10, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:trailofbits:fickling:*:*:*:*:*:python:*:* versions up to (including) 0.1.10 Added Reference Type CISA-ADP: https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697 Types: Exploit, Vendor Advisory Added Reference Type BombadilSystems: https://github.com/trailofbits/fickling/commit/e8408615b63adf034f891f653692ab9b51f0f5af Types: Patch Added Reference Type BombadilSystems: https://github.com/trailofbits/fickling/pull/272 Types: Issue Tracking, Patch Added Reference Type BombadilSystems: https://github.com/trailofbits/fickling/releases/tag/v0.1.11 Types: Release Notes Added Reference Type BombadilSystems: https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 06, 2026
Action Type Old Value New Value Added Reference https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697 Added SSVC {'id': 'CVE-2026-14534', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-06T14:59:25.631510Z'} -
New CVE Received by aa17e1a1-c329-4d6e-a1ed-8d0188aea082
Jul. 04, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'trailofbits', 'product': 'fickling', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'custom', 'lessThanOrEqual': '0.1.10'}, {'status': 'unaffected', 'version': '0.1.11', 'versionType': 'custom'}], 'packageName': 'fickling', 'collectionURL': 'https://pypi.org/project/fickling/', 'defaultStatus': 'unaffected'}] Added Description Trail of Bits fickling versions up to and including 0.1.10 do not include the Python standard library modules _posixsubprocess, site, and atexit in the UNSAFE_IMPORTS denylist (fickle.py). Because these modules are absent from the denylist, fickling's check_safety() function returns LIKELY_SAFE with zero findings for pickle payloads that invoke dangerous functions including _posixsubprocess.fork_exec (C-level process spawner capable of executing arbitrary binaries), site.execsitecustomize (executes arbitrary site customization code), and atexit._run_exitfuncs (triggers all registered exit handler callbacks). The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate; a LIKELY_SAFE verdict causes the payload to be deserialized and executed. This shares the same root cause as CVE-2026-22607 (cProfile), CVE-2025-67748 (pty), and CVE-2025-67747 (marshal/types). OvertlyBadEvals does not flag these modules because they are standard library imports. UnsafeImports does not flag them because they are not in the denylist. The UnusedVariables heuristic is defeated by the SETITEMS opcode pattern. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-184 Added CWE CWE-502 Added Reference https://github.com/trailofbits/fickling/commit/e8408615b63adf034f891f653692ab9b51f0f5af Added Reference https://github.com/trailofbits/fickling/pull/272 Added Reference https://github.com/trailofbits/fickling/releases/tag/v0.1.11 Added Reference https://github.com/trailofbits/fickling/security/advisories/GHSA-m6fh-58r7-x697