CVE-2020-5237 is a high-severity (CVSS 8.8) CWE-23 vulnerability in oneup/uploader-bundle. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-5237 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Relative Path Traversal (CWE-23) in chunked uploads in oneup/uploader-bundle
Real-World Exposure
oneup/uploader-bundle🐘oneup/uploader-bundleReal-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
Multiple relative path traversal vulnerabilities in the oneup/uploader-bundle before 1.9.3 and 2.1.5 allow remote attackers to upload, copy, and modify files on the filesystem (potentially leading to arbitrary code execution) via the (1) filename parameter to BlueimpController.php; the (2) dzchunkindex, (3) dzuuid, or (4) filename parameter to DropzoneController.php; the (5) qqpartindex, (6) qqfilename, or (7) qquuid parameter to FineUploaderController.php; the (8) x-file-id or (9) x-file-name parameter to MooUploadController.php; or the (10) name or (11) chunk parameter to PluploadController.php. This is fixed in versions 1.9.3 and 2.1.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | oneup/uploader-bundle | ≥ 2.0.0&&< 2.1.5 | 2.1.5 |
| 🐘Packagist | oneup/uploader-bundle | ≥ 1.0.0&&< 1.9.3 | 1.9.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for oneup/uploader-bundle. 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 oneup/uploader-bundle to 2.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-5237 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-2020-5237 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-2020-5237. 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-2020-5237 in your dependencies?
O3 detects CVE-2020-5237 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.