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High, CVSS 8.9amended

Fickling has always_check_safety() bypass: pickle.loads and _pickle.loads remain unhooked

GHSA-wccx-j62j-r448

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (fickling 0.1.9), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • PyPI fickling

    Affected
    <= 0.1.8
    Fixed in
    0.1.9

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P · score source
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

Assessment The missing pickle entrypoints pickle.loads, pickle.loads, and pickle.load were added to the hook https://github.com/trailofbits/fickling/commit/8c24c6edabceab156cfd41f4d70b650e1cdad1f7. Original report Summary fickling.alwayschecksafety() does not hook all pickle entry points. pickle.loads, pickle.loads, and pickle.load remain unprotected, enabling malicious payload execution despite global safety mode being enabled. Affected versions <= 0.1.8 (verified on current upstream HEAD as of 2026-03-03) Non-duplication check against published Fickling GHSAs No published advisory covers hook-coverage bypass in runhook(). Existing advisories are blocklist/detection bypasses (runpy, pty, cProfile, marshal/types, builtins, network constructors, OBJ visibility, etc.), not runtime hook coverage parity. Root cause runhook() patches only: - pickle.load - pickle.Unpickler - pickle.Unpickler It does not patch: - pickle.loads - pickle.load - pickle.loads Reproduction (clean upstream)…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-wccx-j62j-r448

  2. Revision 2 · amended ·

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

  3. Revision 1 · created ·

    Published from osv record GHSA-wccx-j62j-r448

Agent brief

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# Patch Next advisory brief: GHSA-wccx-j62j-r448

Advisory: Fickling has `always_check_safety()` bypass: pickle.loads and _pickle.loads remain unhooked
IDs: GHSA-wccx-j62j-r448
Record: https://patchnext.com/advisories/ghsa-wccx-j62j-r448 (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 8.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: fickling 0.1.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI fickling: affected <= 0.1.8; fixed in 0.1.9

## 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-wccx-j62j-r448 (OSV record GHSA-wccx-j62j-r448 lists affected ranges: PyPI fickling >=0 <0.1.9 (fixed))
- Verified: https://github.com/advisories/GHSA-wccx-j62j-r448 (GitHub-reviewed advisory GHSA-wccx-j62j-r448 lists affected ranges: PyPI fickling >=0 <=0.1.8)

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