Arbitrary file upload in Wpmudev Forminator Forms – Contact Form, Payment Form & Custom Builder

CVE-2026-15748

The Forminator Forms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.56.1 via the handle_file_upload function. This is due to insufficient file type validation in handle_file_upload, where the dangerous-extension blocklist performs exact-key matching that is bypassed by pipe-alternative MIME type keys, combined with a public submission handler that trusts attacker-controlled upload field configuration injected via a forged Select field value. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible.

Vulnerability class: Unrestricted File Upload

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.061 (93.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 93rd percentile — 93.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-15748: rose from 0.046 to 0.061.

EPSS over last 30 days · oldest: 0.046 · newest: 0.061 · change: +0.015

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-15748?
CVE-2026-15748 is a critical-severity vulnerability in Wpmudev Forminator Forms – Contact Form, Payment Form & Custom Builder, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2026-08-18.
How severe is CVE-2026-15748?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-15748 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.