trailofbits fickling up to 0.1.10 fickle.py fickling.load incomplete blacklist

Summaryinfo

A vulnerability, which was classified as critical, has been found in trailofbits fickling up to 0.1.10. This vulnerability affects the function fickling.load of the file fickle.py. Performing a manipulation results in incomplete blacklist. This vulnerability is known as CVE-2026-14534. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in trailofbits fickling up to 0.1.10. This affects the function fickling.load of the file fickle.py. The manipulation with an unknown input leads to a incomplete blacklist vulnerability. CWE is classifying the issue as CWE-184. The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete, leading to resultant weaknesses. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was published with Bombadil Systems LLC as GHSA-m6fh-58r7-x697. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-14534 since 07/03/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1562.006 according to MITRE ATT&CK.

Upgrading to version 0.1.11 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch e8408615b63adf034f891f653692ab9b51f0f5af is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Application Server Software

Vendor

• trailofbits

Name

• fickling

Version

• 0.1.0
• 0.1.1
• 0.1.2
• 0.1.3
• 0.1.4
• 0.1.5
• 0.1.6
• 0.1.7
• 0.1.8
• 0.1.9
• 0.1.10

License

• open-source

Website

• Product: https://github.com/trailofbits/fickling/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion