GHSA-FR76-5637-W3G9
Vulnerability from github – Published: 2026-03-25 20:00 – Updated: 2026-03-27 21:35Summary
The code16/sharp Laravel admin panel package contains a vulnerability in its file upload endpoint that allows authenticated users to bypass all file type restrictions.
Details
The upload endpoint within the ApiFormUploadController accepts a client-controlled validation_rule parameter. This parameter is directly passed into the Laravel validator without sufficient server-side enforcement. By intercepting the request and sending validation_rule[]=file, an attacker can completely bypass all MIME type and file extension restrictions. The vulnerable code is located in src/Http/Controllers/Api/ApiFormUploadController.php at line 24.
Impact
This vulnerability leads to several critical security risks:
Attackers can upload arbitrary files, including PHP webshells, to the server. For more details on the package, visit: https://github.com/code16/sharp
MIME type and extension validation can be bypassed entirely via client-controlled rules. Review the CWE definition here: https://cwe.mitre.org/data/definitions/434.html
If the storage disk is configured to be publicly accessible, this can lead to Remote Code Execution (RCE). See the vendor repository: https://github.com/code16/sharp
(Note: Under default configurations, executing uploaded PHP files directly is not possible unless a public disk configuration is in place.)
Patches
This issue has been addressed by removing the client-controlled validation rules and strictly defining upload rules server-side. The fix is available in pull request https://github.com/code16/sharp/pull/714.
Workarounds
- Restrict Disk Access: Ensure that the storage disk used for Sharp uploads is strictly private. Under default configurations, an attacker cannot directly execute uploaded PHP files unless a public disk configuration is explicitly used. For more details on Laravel disk configurations, visit: https://laravel.com/docs/13.x/filesystem
Credits
Reported by zaurgsynv.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "code16/sharp"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "9.20.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-33687"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-25T20:00:24Z",
"nvd_published_at": "2026-03-26T22:16:31Z",
"severity": "HIGH"
},
"details": "### Summary \nThe `code16/sharp` Laravel admin panel package contains a vulnerability in its file upload endpoint that allows authenticated users to bypass all file type restrictions.\n\n### Details\nThe upload endpoint within the `ApiFormUploadController` accepts a client-controlled `validation_rule` parameter. This parameter is directly passed into the Laravel validator without sufficient server-side enforcement. By intercepting the request and sending `validation_rule[]=file`, an attacker can completely bypass all MIME type and file extension restrictions. The vulnerable code is located in `src/Http/Controllers/Api/ApiFormUploadController.php` at line 24.\n\n### Impact\nThis vulnerability leads to several critical security risks:\n\nAttackers can upload arbitrary files, including PHP webshells, to the server. For more details on the package, visit: https://github.com/code16/sharp\n\nMIME type and extension validation can be bypassed entirely via client-controlled rules. Review the CWE definition here: https://cwe.mitre.org/data/definitions/434.html\n\nIf the storage disk is configured to be publicly accessible, this can lead to Remote Code Execution (RCE). See the vendor repository: https://github.com/code16/sharp\n\n(Note: Under default configurations, executing uploaded PHP files directly is not possible unless a public disk configuration is in place.)\n\n### Patches\nThis issue has been addressed by removing the client-controlled validation rules and strictly defining upload rules server-side. The fix is available in pull request https://github.com/code16/sharp/pull/714.\n\n### Workarounds\n- Restrict Disk Access: Ensure that the storage disk used for Sharp uploads is strictly private. Under default configurations, an attacker cannot directly execute uploaded PHP files unless a public disk configuration is explicitly used. For more details on Laravel disk configurations, visit: https://laravel.com/docs/13.x/filesystem\n\n### Credits\nReported by [zaurgsynv](https://github.com/zaurgsynv).",
"id": "GHSA-fr76-5637-w3g9",
"modified": "2026-03-27T21:35:55Z",
"published": "2026-03-25T20:00:24Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/code16/sharp/security/advisories/GHSA-fr76-5637-w3g9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33687"
},
{
"type": "WEB",
"url": "https://github.com/code16/sharp/pull/714"
},
{
"type": "PACKAGE",
"url": "https://github.com/code16/sharp"
},
{
"type": "WEB",
"url": "https://github.com/code16/sharp/releases/tag/v9.20.0"
},
{
"type": "WEB",
"url": "https://laravel.com/docs/13.x/filesystem"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Sharp has Unrestricted File Upload via Client-Controlled Validation Rules"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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