CVE-2026-33687

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.

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.

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.)

The application accepts file uploads without adequately restricting the file type or content. Typical impact: remote code execution if the uploaded file can be served and executed on the server.

CVE-2026-33687 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (9.20.0); upgrading removes the vulnerable code path.

Kodem intelligence

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.

1. What is CVE-2026-33687? CVE-2026-33687 is a high-severity unrestricted upload of dangerous file types vulnerability in code16/sharp (composer), affecting versions < 9.20.0. It is fixed in 9.20.0. The application accepts file uploads without adequately restricting the file type or content.
2. How severe is CVE-2026-33687? CVE-2026-33687 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of code16/sharp are affected by CVE-2026-33687? code16/sharp (composer) versions < 9.20.0 is affected.
4. Is there a fix for CVE-2026-33687? Yes. CVE-2026-33687 is fixed in 9.20.0. Upgrade to this version or later.
5. Is CVE-2026-33687 exploitable, and should I be worried? Whether CVE-2026-33687 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-33687 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-33687? Upgrade code16/sharp to 9.20.0 or later.