Vulnerability · Published Sep 17, 2026 · Assigned by Wordfence
CVE-2026-87796Multi Uploader for Gravity Forms <= 1.1.9 - Unauthenticated Arbitrary File Upload via Chunked File Upload
Critical 9.8
In plain English
A critical-severity unrestricted file upload in Multi Uploader for Gravity Forms from sh1zen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 67% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
The Multi Uploader for Gravity Forms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.1.9 via the move_file function. This is due to insufficient file type validation during chunked upload handling. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| sh1zen | Multi Uploader for Gravity Forms | 0 – through 1.1.9 |
Weakness: CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/47337bc1-fa3d-470c-9524-859295261017?source=cve
- https://plugins.trac.wordpress.org/browser/gf-multi-uploader/tags/1.1.9/inc/GFMU_FileUploader.php#L560
- https://plugins.trac.wordpress.org/browser/gf-multi-uploader/tags/1.1.9/inc/GFMU_FileUploader.php#L319
- https://plugins.trac.wordpress.org/browser/gf-multi-uploader/tags/1.1.9/inc/GFMU_FileUploader.php#L322
- https://plugins.trac.wordpress.org/browser/gf-multi-uploader/tags/1.1.9/inc/GFMUHandlePluploader.class.php#L257
- https://plugins.trac.wordpress.org/browser/gf-multi-uploader/tags/1.1.9/GFMUAddon.class.php#L125