CVE-2026-33687
Sharp has Unrestricted File Upload via Client-Controlled Validation Rules
Description
Sharp is a content management framework built for Laravel as a package. Versions prior to 9.20.0 contain a vulnerability in the file upload endpoint that allows authenticated users to bypass all file type restrictions. 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. This issue has been addressed in version 9.20.0 by removing the client-controlled validation rules and strictly defining upload rules server-side. As a workaround, 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.
INFO
Published Date :
March 26, 2026, 10:16 p.m.
Last Modified :
April 2, 2026, 5:22 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update Sharp to version 9.20.0 or later.
- Ensure Sharp upload storage is configured as private.
- Review file upload validation rules server-side.
- Remove client-controlled validation rules.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33687.
| URL | Resource |
|---|---|
| https://github.com/code16/sharp/pull/714 | Issue Tracking Patch |
| https://github.com/code16/sharp/releases/tag/v9.20.0 | Product |
| https://github.com/code16/sharp/security/advisories/GHSA-fr76-5637-w3g9 | Vendor Advisory |
| https://laravel.com/docs/13.x/filesystem | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33687 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33687
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33687 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33687 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:code16:sharp:*:*:*:*:*:*:*:* versions up to (excluding) 9.20.0 Added Reference Type GitHub, Inc.: https://github.com/code16/sharp/pull/714 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/code16/sharp/releases/tag/v9.20.0 Types: Product Added Reference Type GitHub, Inc.: https://github.com/code16/sharp/security/advisories/GHSA-fr76-5637-w3g9 Types: Vendor Advisory Added Reference Type GitHub, Inc.: https://laravel.com/docs/13.x/filesystem Types: Third Party Advisory -
New CVE Received by [email protected]
Mar. 26, 2026
Action Type Old Value New Value Added Description Sharp is a content management framework built for Laravel as a package. Versions prior to 9.20.0 contain a vulnerability in the file upload endpoint that allows authenticated users to bypass all file type restrictions. 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. This issue has been addressed in version 9.20.0 by removing the client-controlled validation rules and strictly defining upload rules server-side. As a workaround, 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-434 Added Reference https://github.com/code16/sharp/pull/714 Added Reference https://github.com/code16/sharp/releases/tag/v9.20.0 Added Reference https://github.com/code16/sharp/security/advisories/GHSA-fr76-5637-w3g9 Added Reference https://laravel.com/docs/13.x/filesystem