Laravel Backpack CRUD: Arbitrary file deletion via attacker-controlled clear_<attr>[] in HasUploadFields::uploadMultipleFilesToDisk

Summary

HasUploadFields::uploadMultipleFilesToDisk (in src/app/Models/Traits/HasUploadFields.php) reads file paths from the clear_<attribute>[] request input and deletes them from the configured storage disk without verifying that the paths belong to the current model record.

An authenticated user with Update access on any CRUD that wires uploadMultipleFilesToDisk as a model mutator (the pattern documented in the v5.x upload_multiple field guide) can supply arbitrary disk-relative paths in clear_<attr>[] to delete files that were never associated with the record they are editing.

The safe pattern already exists in the codebase: src/app/Library/Uploaders/MultipleFiles.php intersects the requested deletions against the files currently stored in the database column before calling Storage::disk()->delete(). The trait method lacks that intersection.

Affected code

• src/app/Models/Traits/HasUploadFields.php — uploadMultipleFilesToDisk (primary sink)
• src/app/Models/Traits/CrudTrait.php — mixes HasUploadFields into all Backpack-managed models

The vulnerability is present in all 5.x, 6.x < 6.8.12, and 7.x < 7.0.35 releases.

Impact

An attacker with low-privilege Backpack admin access (e.g. a content editor) can delete any file under the configured disk root: other records' attachments, shared assets, or files placed on the same disk for operational purposes. No confidentiality impact (files cannot be read, only deleted).

CWE-285 (Authorization Bypass) / CWE-639 (IDOR on file deletion)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H = 8.1 High

Fix

Intersect $files_to_clear against the filenames currently persisted on the model before calling delete(), mirroring the logic already present in MultipleFiles::uploadFiles. Fixed in 6.8.12 and 7.0.35.

Deployments still using the uploadMultipleFilesToDisk mutator pattern from the v5.x docs should migrate to the Uploader API (MultipleFiles::class via config/backpack/crud.php), which applies the safe intersection automatically.

Credits

Reported by Vishal Shukla (@shukla304).