CVE-2025-71339: Picklescan Remote Code Execution Vulnerability

MODERATE
Advisory Identifier: GHSA-6556-fwc2-fg2p
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CVSS 8.1
CWE-502 CWE-94
Published
Advisory Summary

CVE-2025-71339 is a MODERATE (CVSS 8.1) remote code execution vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Picklescan libraries in the PyPI ecosystem. The issue involves picklescan is vulnerable to rce through missing detection when calling numpy.f2py.crackfortran._eval_length. Remediation is available by upgrading affected packages to version 0.0.33.

CVE-2025-71339 at a Glance

CVE Identifier CVE-2025-71339
GHSA Identifier GHSA-6556-fwc2-fg2p
Severity MODERATE
CVSS v3.1 Base Score 8.1
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Picklescan
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2025-71339

To remediate this vulnerability, upgrade all affected Picklescan dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

picklescan fixed: 0.0.33 
pip install picklescan>=0.0.33
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show picklescan

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-71339, inspect your installed packages using pip:

pip show picklescan

Analyze the terminal output to locate any version of Picklescan in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.0.33), your application is affected.

Note: The pip show picklescan command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Picklescan, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary Picklescan uses the `numpy.f2py.crackfortran._eval_length` function (a NumPy F2PY helper) to execute arbitrary Python code during unpickling. ### Details Picklescan 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. ### PoC ```python class PoC: def __reduce__(self): from numpy.f2py.crackfortran import _eval_length return _eval_length, ("__import__('os').system('whoami')", None) ``` ### Impact - Arbitrary code execution on the victim machine once they load the “scanned as safe” pickle / model file. - Affects any workflow relying on Picklescan to vet untrusted pickle / PyTorch artifacts. - Enables supply‑chain poisoning of shared model files. ### Credits - [ac0d3r](https://github.com/ac0d3r) - [Tong Liu](https://lyutoon.github.io), Institute of information engineering, CAS

CVE-2025-71339 Affected Picklescan Versions

1 component(s)
Fixed Versions:
0.0.33
Product / Package Ecosystem Affected Versions Fixed Version
picklescan
pypi/picklescan
PyPI
< 0.0.33
0.0.33

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mmaitre314/picklescan/security/advisories/GHSA-6556-fwc2-fg2p
NVD — CVE-2025-71339 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-71339
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan/pull/53
Security Fix Commit FIX COMMIT
https://github.com/mmaitre314/picklescan/commit/70c1c6c31beb6baaf52c8db1b6c3c0e84a6f9dab
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-6556-fwc2-fg2p
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan
Picklescan Release RELEASE
https://github.com/mmaitre314/picklescan/releases/tag/v0.0.33
Picklescan Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/picklescan/PYSEC-2026-1783.yaml
pypi.org/project/picklescan WEB
https://pypi.org/project/picklescan
www.vulncheck.com/advisories/picklesc... WEB
https://www.vulncheck.com/advisories/picklescan-arbitrary-code-execution-via-numpy-f2py-crackfortran-eval-length-gadget

Frequently Asked Questions

What is CVE-2025-71339?
CVE-2025-71339 is a security vulnerability in Picklescan involving Picklescan is vulnerable to RCE through missing detection when calling numpy.f2py.crackfortran._eval_length under CWE-502: Deserialization of Untrusted Data.
Which Picklescan versions are affected?
Affected versions include releases prior to 0.0.33 across affected packages: picklescan.
What version fixes CVE-2025-71339?
Upgrading to 0.0.33 (or the latest patched release for your respective branch) resolves the vulnerability.
Is picklescan affected?
Yes, picklescan is affected in releases prior to 0.0.33. Upgrade your dependency to 0.0.33 or later.
What is the CVSS score of CVE-2025-71339?
CVE-2025-71339 has a CVSS v3.1 base score of 8.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2025-71339?
CVE-2025-71339 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check PyPI dependencies for CVE-2025-71339?
Run the dependency tree command: 'pip show picklescan'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6556-fwc2-fg2p",
  "modified" : "2026-07-18T17:27:24Z",
  "published" : "2025-12-30T15:20:14Z",
  "aliases" : [ "CVE-2025-71339" ],
  "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",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"
  }, {
    "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "picklescan"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.33"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/security/advisories/GHSA-6556-fwc2-fg2p"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-71339"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/pull/53"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/commit/70c1c6c31beb6baaf52c8db1b6c3c0e84a6f9dab"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-6556-fwc2-fg2p"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mmaitre314/picklescan"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/releases/tag/v0.0.33"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/picklescan/PYSEC-2026-1783.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://pypi.org/project/picklescan"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/picklescan-arbitrary-code-execution-via-numpy-f2py-crackfortran-eval-length-gadget"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502", "CWE-94" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-30T15:20:14Z",
    "nvd_published_at" : "2026-06-22T22:16:45Z"
  }
}