Unauthenticated file upload via pre-validation file move
Published Sep 17, 2026 · Updated Sep 19, 2026
Arbitrary file upload in sh1zen Multi Uploader for Gravity Forms 1.1.9 and earlier allows remote attackers to write files via chunked uploads. The move_file path copies an assembled chunked file into the web-accessible upload directory before validateUploadedFile checks its type. No authentication is required; code execution follows only where the server executes the uploaded file type.
Summary
What happened
Arbitrary file upload in sh1zen Multi Uploader for Gravity Forms 1.1.9 and earlier allows remote attackers to write files via chunked uploads. The move_file path copies an assembled chunked file into the web-accessible upload directory before validateUploadedFile checks its type. No authentication is required; code execution follows only where the server executes the uploaded file type.
The record
- CVE
- CVE-2026-87796
- Published
- Sep 17, 2026
- Updated
- Sep 19, 2026
- Vendor
- sh1zen
- Product
- Multi Uploader for Gravity Forms
- Classifications
- CWE-434, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 17, 2026CVE publishedPublication date reported by the CVE source.
- Sep 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=1.1.9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Abraxas Labs CVE-2026-87796 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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