Sharp has Unrestricted File Upload via Client-Controlled Validation Rules

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-33687: 0.53% estimated exploitation activity in the next 30 days; percentile 44.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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 validationrule parameter. This parameter is directly passed into the Laravel validator without sufficient server-side enforcement. By intercepting the request and sending validationrule[]=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:…

Published by the source

25 Mar 2026, 20:00 UTC

Last modified by the source

27 Mar 2026, 21:35 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fr76-5637-w3g9

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# Patch Next advisory brief: CVE-2026-33687

Advisory: Sharp has Unrestricted File Upload via Client-Controlled Validation Rules
IDs: CVE-2026-33687, GHSA-fr76-5637-w3g9
Record: https://patchnext.com/advisories/cve-2026-33687 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code16/sharp 9.20.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist code16/sharp: affected < 9.20.0; fixed in 9.20.0

## Suggested inspection (read-only)
- Packagist code16/sharp: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code16/sharp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-fr76-5637-w3g9 (GitHub-reviewed advisory GHSA-fr76-5637-w3g9 lists affected ranges: Packagist code16/sharp >=0 <9.20.0)

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