Fickling has missing detection for marshal.loads and types.FunctionType in unsafe modules list

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.1 · 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 · score source

EPSS

• CVE-2025-67747: 0.28% estimated exploitation activity in the next 30 days; percentile 20.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Fickling Assessment Based on the test case provided in the original report below, this bypass was caused by marshal and types missing from the block list of unsafe module imports, Fickling started blocking both modules to address this issue. This was fixed in https://github.com/trailofbits/fickling/pull/186. The crash is unrelated and has no security impact—it will be addressed separately. Original report Summary There's missing detection for the python modules, marshal.loads and types.FunctionType and Fickling throws unhandled ValueErrors when the stack is deliberately exhausted. Details Fickling simply doesn't have the aforementioned modules in its list of unsafe imports and therefore it fails to get detected. PoC The following is a disassembled view of a malicious pickle file that uses these modules: When analyzing this modified file, safetyresult.json shows: Furthermore, when we run fickling -s <pathtomaliciousfile, we also encounter this error: Impact This allows an attacker to…

Published by the source

15 Dec 2025, 23:35 UTC

Last modified by the source

7 Jul 2026, 17:56 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-565g-hwwr-4pp3

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-565g-hwwr-4pp3

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# Patch Next advisory brief: CVE-2025-67747

Advisory: Fickling has missing detection for marshal.loads and types.FunctionType in unsafe modules list
IDs: CVE-2025-67747, GHSA-565g-hwwr-4pp3
Record: https://patchnext.com/advisories/cve-2025-67747 (revision 3, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: fickling 0.1.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI fickling: affected < 0.1.6; fixed in 0.1.6

## Suggested inspection (read-only)
- `python -m pip show fickling`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on fickling.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-565g-hwwr-4pp3 (OSV record GHSA-565g-hwwr-4pp3 lists affected ranges: PyPI fickling >=0 <0.1.6 (fixed))
- Verified: https://github.com/advisories/GHSA-565g-hwwr-4pp3 (GitHub-reviewed advisory GHSA-565g-hwwr-4pp3 lists affected ranges: PyPI fickling >=0 <0.1.6)

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