Picklescan Bypasses Unsafe Globals Check using pty.spawn

Exploitation

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

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2025-71322: 0.38% estimated exploitation activity in the next 30 days; percentile 32.50 (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.

Summary The vulnerability allows malicious actors to bypass PickleScan's unsafe globals check, leading to potential arbitrary code execution. The issue stems from the absence of the pty library (more specifically, of the pty.spawn function) from PickleScan's list of unsafe globals. This vulnerability allows attackers to disguise malicious pickle payloads within files that would otherwise be scanned for pickle-based threats. Details For 2025's HeroCTF, there was a challenge named Irreductible 2 where players would need to bypass the latest versions of PickleScan and Fickling to gain code execution. The challenge writeup, files and solve script have all been released. The intended way was to use pty.spawn but some players found alternative solutions. PoC - Run the following Python code to generate the PoC pickle file. - Run PickleScan on the generated pickle file. <img width="936" height="311" alt="picklescanbypassptyspawn"…

Published by the source

29 Dec 2025, 15:26 UTC

Last modified by the source

7 Jul 2026, 17:57 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hgrh-qx5j-jfwx

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hgrh-qx5j-jfwx

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# Patch Next advisory brief: CVE-2025-71322

Advisory: Picklescan Bypasses Unsafe Globals Check using pty.spawn
IDs: CVE-2025-71322, GHSA-hgrh-qx5j-jfwx
Record: https://patchnext.com/advisories/cve-2025-71322 (revision 2, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: picklescan 0.0.33. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI picklescan: affected < 0.0.33; fixed in 0.0.33

## Suggested inspection (read-only)
- `python -m pip show picklescan`: 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 picklescan.
- 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-hgrh-qx5j-jfwx (OSV record GHSA-hgrh-qx5j-jfwx lists affected ranges: PyPI picklescan >=0 <0.0.33 (fixed))
- Verified: https://github.com/advisories/GHSA-hgrh-qx5j-jfwx (GitHub-reviewed advisory GHSA-hgrh-qx5j-jfwx lists affected ranges: PyPI picklescan >=0 <0.0.33)

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