GHSA-8Q2W-PV9P-MJVC

Vulnerability from github – Published: 2026-08-20 18:38 – Updated: 2026-08-20 18:38
VLAI
Summary
Laravel Backpack CRUD: HasUploadFields keeps the attacker-supplied file extension — public-disk uploads of `shell.php` reach the webserver
Details

Summary

HasUploadFields (used via CrudTrait on Backpack-managed models) and the withFiles() uploader preserve the client-supplied file extension without validation. On installations using a public disk with php artisan storage:link, this allows an authenticated administrator to upload a file with a server-executable extension that the web server will pass to the PHP interpreter - if no MIME or other type of upload validation is present.

Details

The uploadFileToDisk and uploadMultipleFilesToDisk methods hash the filename stem but write the client-supplied extension to disk verbatim — no allowlist, blocklist, or MIME check is applied inside the trait itself.

The newer withFiles() path (via FileNameGenerator) resolves the extension from the file's MIME type rather than the client filename, but also does not block server-executable types.

Applications that follow the Backpack quickstart without adding explicit mimes: or mimetypes: validation rules in their form requests are affected.

Impact

An authenticated administrator with access to an upload-enabled CRUD panel, on a site using the public disk with web-accessible storage and no MIME type validation, can upload a server-executable file and achieve remote code execution.

Conditions required for exploitation:

  • Authenticated admin access to a Backpack CRUD panel
  • An upload field with no mimes: / mimetypes: validation rule
  • The public disk in use (standard pattern for web-visible uploads)
  • php artisan storage:link in place
  • A web server + PHP-FPM stack (default on most hosts)

Fix

A denylist for server-executable extensions has been added to both HasUploadFields and FileNameGenerator. Image-typed fields now additionally enforce an allowlist. This is defence-in-depth — it does not replace application-level validation.

Recommended developer action

Review all upload fields and add explicit mimes: or mimetypes: validation in your form requests or field definitions. Refer to the Backpack field documentation for examples.

Reported by Vishal Shukla (@shukla304) via sechub.dev.

Severity
6.6 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "backpack/crud"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.0"
            },
            {
              "fixed": "6.8.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "backpack/crud"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.0.38"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54177"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-434"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-20T18:38:34Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\n`HasUploadFields` (used via `CrudTrait` on Backpack-managed models) and the `withFiles()` uploader preserve the client-supplied file extension without validation. On installations using a `public` disk with `php artisan storage:link`, this allows an authenticated administrator to upload a file with a server-executable extension that the web server will pass to the PHP interpreter - if no MIME or other type of upload validation is present.\n\n## Details\n\nThe `uploadFileToDisk` and `uploadMultipleFilesToDisk` methods hash the filename stem but write the client-supplied extension to disk verbatim \u2014 no allowlist, blocklist, or MIME check is applied inside the trait itself.\n\nThe newer `withFiles()` path (via `FileNameGenerator`) resolves the extension from the file\u0027s MIME type rather than the client filename, but also does not block server-executable types.\n\nApplications that follow the Backpack quickstart without adding explicit `mimes:` or `mimetypes:` validation rules in their form requests are affected.\n\n## Impact\n\nAn authenticated administrator with access to an upload-enabled CRUD panel, on a site using the `public` disk with web-accessible storage and no MIME type validation, can upload a server-executable file and achieve remote code execution.\n\n**Conditions required for exploitation:**\n\n- Authenticated admin access to a Backpack CRUD panel\n- An upload field with no `mimes:` / `mimetypes:` validation rule\n- The `public` disk in use (standard pattern for web-visible uploads)\n- `php artisan storage:link` in place\n- A web server + PHP-FPM stack (default on most hosts)\n\n## Fix\n\nA denylist for server-executable extensions has been added to both `HasUploadFields` and `FileNameGenerator`. Image-typed fields now additionally enforce an allowlist. This is defence-in-depth \u2014 it does not replace application-level validation.\n\n## Recommended developer action\n\nReview all upload fields and add explicit `mimes:` or `mimetypes:` validation in your form requests or field definitions. Refer to the [Backpack field documentation](https://backpackforlaravel.com/docs) for examples.\n\n---\n\nReported by Vishal Shukla ([@shukla304](https://github.com/shukla304)) via sechub.dev.",
  "id": "GHSA-8q2w-pv9p-mjvc",
  "modified": "2026-08-20T18:38:34Z",
  "published": "2026-08-20T18:38:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Laravel-Backpack/CRUD/security/advisories/GHSA-8q2w-pv9p-mjvc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Laravel-Backpack/CRUD/pull/5993"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Laravel-Backpack/CRUD"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Laravel-Backpack/CRUD/releases/tag/6.8.14"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Laravel-Backpack/CRUD/releases/tag/7.0.38"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Laravel Backpack CRUD: HasUploadFields keeps the attacker-supplied file extension \u2014 public-disk uploads of `shell.php` reach the webserver"
}



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