id: PYSEC-2026-1783
published: "2026-07-07T16:03:14.498992Z"
modified: "2026-07-07T17:25:02.114122Z"
aliases:
- CVE-2025-71339
- GHSA-6556-fwc2-fg2p
summary: Picklescan is vulnerable to RCE through missing detection when calling numpy.f2py.crackfortran._eval_length
details: "### Summary\n\nPicklescan uses the `numpy.f2py.crackfortran._eval_length` function (a NumPy F2PY helper) to execute arbitrary Python code during unpickling.\n\n### Details\n\nPicklescan fails to detect a malicious pickle that uses the gadget `numpy.f2py.crackfortran._eval_length` in `__reduce__`, allowing arbitrary command execution when the pickle is loaded. A crafted object returns this function plus attacker‑controlled arguments; the scan reports the file as safe, but pickle.load() triggers execution.\n\n### PoC\n```python\nclass PoC:\n    def __reduce__(self):\n        from numpy.f2py.crackfortran import _eval_length\n        return _eval_length, (\"__import__('os').system('whoami')\", None)\n```\n\n### Impact\n\n- Arbitrary code execution on the victim machine once they load the “scanned as safe” pickle / model file.\n- Affects any workflow relying on Picklescan to vet untrusted pickle / PyTorch artifacts.\n- Enables supply‑chain poisoning of shared model files.\n\n### Credits\n- [ac0d3r](https://github.com/ac0d3r)\n- [Tong Liu](https://lyutoon.github.io), Institute of information engineering, CAS"
affected:
- package:
    name: picklescan
    ecosystem: PyPI
    purl: pkg:pypi/picklescan
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: "0"
    - fixed: 0.0.33
  versions:
  - 0.0.1
  - 0.0.10
  - 0.0.11
  - 0.0.12
  - 0.0.13
  - 0.0.14
  - 0.0.15
  - 0.0.16
  - 0.0.17
  - 0.0.18
  - 0.0.19
  - 0.0.2
  - 0.0.20
  - 0.0.21
  - 0.0.22
  - 0.0.23
  - 0.0.24
  - 0.0.25
  - 0.0.26
  - 0.0.27
  - 0.0.28
  - 0.0.29
  - 0.0.3
  - 0.0.30
  - 0.0.31
  - 0.0.32
  - 0.0.4
  - 0.0.5
  - 0.0.6
  - 0.0.7
  - 0.0.8
  - 0.0.9
references:
- type: WEB
  url: https://github.com/mmaitre314/picklescan/security/advisories/GHSA-6556-fwc2-fg2p
- type: WEB
  url: https://github.com/mmaitre314/picklescan/pull/53
- type: WEB
  url: https://github.com/mmaitre314/picklescan/commit/70c1c6c31beb6baaf52c8db1b6c3c0e84a6f9dab
- type: PACKAGE
  url: https://github.com/mmaitre314/picklescan
- type: WEB
  url: https://github.com/mmaitre314/picklescan/releases/tag/v0.0.33
- type: PACKAGE
  url: https://pypi.org/project/picklescan
- type: ADVISORY
  url: https://github.com/advisories/GHSA-6556-fwc2-fg2p
- type: ADVISORY
  url: https://nvd.nist.gov/vuln/detail/CVE-2025-71339
severity:
- type: CVSS_V4
  score: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P