CVE-2026-33687
HIGHCVE-2026-33687 is a high-severity (CVSS 8.8) Unrestricted File Upload vulnerability in code16/sharp. O3 Security confirms whether CVE-2026-33687 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Sharp has Unrestricted File Upload via Client-Controlled Validation Rules
Blast Radius
code16/sharpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | code16/sharp | all versions | 9.20.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code16/sharp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update code16/sharp to 9.20.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33687 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-33687 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-33687. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33687 in your dependencies?
O3 detects CVE-2026-33687 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.