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Medium, CVSS 6.9amended

fickling modules linecache, difflib and gc are missing from the unsafe modules blocklist

GHSA-r48f-3986-4f9c

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (fickling 0.1.10), 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
    <= 0.1.9
    Fixed in
    0.1.10

Sources

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

As published by the source; long descriptions are shortened.

Our analysis As stated in the project's security policy, we also don't consider UnusedVariables bypasses to be security issues. We added several unsafe modules mentioned by the reporter in advisory comments to the blocklist (https://github.com/trailofbits/fickling/commit/7f39d97258217ee2c21a1f5031d4a6d7343eb30d). Original report Title: UnusedVariables analysis bypass via BUILD opcode Arbitrary File Read through fickling.load() Summary Two independent bugs in fickling's AST-based static analysis combine to allow a malicious pickle file to execute arbitrary stdlib function calls - including reading sensitive files - while checksafety() returns Severity.LIKELYSAFE and fickling.load() completes without raising UnsafeFileError. A server using fickling.load() as a security gate before deserializing untrusted pickle data (its documented use case) is fully bypassed. The attacker receives the contents of any file readable by the server process as the return value of fickling.load(). Details…

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

    Amended from ghsa record GHSA-r48f-3986-4f9c

  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-r48f-3986-4f9c

Agent brief

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# Patch Next advisory brief: GHSA-r48f-3986-4f9c

Advisory: fickling modules linecache, difflib and gc are missing from the unsafe modules blocklist
IDs: GHSA-r48f-3986-4f9c
Record: https://patchnext.com/advisories/ghsa-r48f-3986-4f9c (revision 3, source checked 26 Oct 2026, 13:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: fickling 0.1.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI fickling: affected <= 0.1.9; fixed in 0.1.10

## 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-r48f-3986-4f9c (OSV record GHSA-r48f-3986-4f9c lists affected ranges: PyPI fickling >=0 <0.1.10 (fixed))
- Verified: https://github.com/advisories/GHSA-r48f-3986-4f9c (GitHub-reviewed advisory GHSA-r48f-3986-4f9c lists affected ranges: PyPI fickling >=0 <=0.1.9)

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