CVE-2021-43421: Studio 42/elfinder ElFinder Unrestricted File Upload Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-x4jx-hjwf-gc99
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CVSS 9.8
CWE-434
Published
Advisory Summary

CVE-2021-43421 is a CRITICAL (CVSS 9.8) elfinder unrestricted file upload vulnerability vulnerability (CWE-434: Unrestricted Upload of File with Dangerous Type) affecting Studio 42/elfinder libraries in the Packagist ecosystem. The issue involves elfinder unrestricted file upload vulnerability. Remediation is available by upgrading affected packages to version 2.1.60.

CVE-2021-43421 at a Glance

CVE Identifier CVE-2021-43421
GHSA Identifier GHSA-x4jx-hjwf-gc99
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-434: Unrestricted Upload of File with Dangerous Type
Affected Product Studio 42/elfinder
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/A:H).

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 High (I:H)
Availability High (A:H)

How to Fix CVE-2021-43421

To remediate this vulnerability, upgrade all affected Studio 42/elfinder dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

studio-42/elfinder fixed: 2.1.60 
Upgrade studio-42/elfinder to 2.1.60
Verify Direct and Transitive Dependencies

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

inspect dependencies for studio-42/elfinder

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-43421, inspect your project dependencies for Studio 42/elfinder:

inspect dependencies for studio-42/elfinder

Analyze the terminal output to locate any version of Studio 42/elfinder in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.60), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-434: Unrestricted Upload of File with Dangerous Type, where the product allows the upload or transfer of dangerous file types that are automatically processed within its environment. In Studio 42/elfinder, 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

A File Upload vulnerability exists in Studio-42 elFinder 2.0.4 to 2.1.59 via `connector.minimal.php`, which allows a remote malicious user to upload arbitrary files and execute PHP code.

CVE-2021-43421 Affected Studio 42/elfinder Versions

1 component(s)
Fixed Versions:
2.1.60
Product / Package Ecosystem Affected Versions Fixed Version
studio-42/elfinder
 Packagist
≥ 2.0.4
< 2.1.60
2.1.60

References

NVD — CVE-2021-43421 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-43421
Studio 42/elfinder Source Repository REPOSITORY
https://github.com/Studio-42/elFinder/issues/3429
Security Fix Commit FIX COMMIT
https://github.com/Studio-42/elFinder/commit/c08bcbfa722d758d01975799b7036951eb5d33cb
Studio 42/elfinder Source Repository REPOSITORY
https://github.com/Studio-42/elFinder
twitter.com/infosec_90/status/1... WEB
https://twitter.com/infosec_90/status/1455180286354919425

Frequently Asked Questions

What is CVE-2021-43421?
CVE-2021-43421 is a security vulnerability in Studio 42/elfinder involving elFinder Unrestricted File Upload vulnerability under CWE-434: Unrestricted Upload of File with Dangerous Type.
Which Studio 42/elfinder versions are affected?
Affected versions include releases prior to 2.1.60 across affected packages: studio-42/elfinder.
What version fixes CVE-2021-43421?
Upgrading to 2.1.60 (or the latest patched release for your respective branch) resolves the vulnerability.
Is studio-42/elfinder affected?
Yes, studio-42/elfinder is affected in releases prior to 2.1.60. Upgrade your dependency to 2.1.60 or later.
What is the CVSS score of CVE-2021-43421?
CVE-2021-43421 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-43421?
CVE-2021-43421 is classified under CWE-434: Unrestricted Upload of File with Dangerous Type (The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.).
How can I check Packagist dependencies for CVE-2021-43421?
Run the dependency tree command: 'inspect dependencies for studio-42/elfinder'. 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-x4jx-hjwf-gc99",
  "modified" : "2024-01-10T19:33:07Z",
  "published" : "2022-04-08T00:00:23Z",
  "aliases" : [ "CVE-2021-43421" ],
  "summary" : "elFinder Unrestricted File Upload vulnerability",
  "details" : "A File Upload vulnerability exists in Studio-42 elFinder 2.0.4 to 2.1.59 via `connector.minimal.php`, which allows a remote malicious user to upload arbitrary files and execute PHP code.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "studio-42/elfinder"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.4"
      }, {
        "fixed" : "2.1.60"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-43421"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Studio-42/elFinder/issues/3429"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Studio-42/elFinder/commit/c08bcbfa722d758d01975799b7036951eb5d33cb"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Studio-42/elFinder"
  }, {
    "type" : "WEB",
    "url" : "https://twitter.com/infosec_90/status/1455180286354919425"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-01-10T19:33:07Z",
    "nvd_published_at" : "2022-04-07T17:15:00Z"
  }
}