External risk intelligence

Sigma Forms Pro for WordPress Unrestricted File Upload Remote Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-14494

The vulnerability affects a WordPress plugin designed to handle public-facing form submissions, such as job applications and support tickets. These features are intended to be accessible to unauthenticated users over the internet by design, placing the vulnerable entry point directly on the public-facing edge of the web server.

Unrestricted File Upload

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in the Sigma Forms Pro WordPress plugin that could allow unauthenticated attackers to execute arbitrary code on your web servers. This issue arises from insecure file upload handling within the plugin's form submission process, potentially affecting default configurations.

Unauthenticated code execution via file uploads.
Affects common customer-facing website forms.
Confirm relevance and exposure to WordPress sites.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can exploit this vulnerability by submitting a specially crafted file through a form on a WordPress site using the Sigma Forms Pro plugin. The plugin's insecure handling of file uploads allows arbitrary file types to be uploaded, including executable code, which can then be run on the server. This can lead to a complete compromise of the website.

No authentication required.
Upload a malicious file via form submission.
Remote code execution and server compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow unauthenticated attackers to execute arbitrary code on the server when users submit forms through the Sigma Forms Pro plugin. Specifically, if the plugin's file upload functionality is used without proper configuration, it may bypass security checks, enabling malicious file uploads that lead to code execution. This is particularly concerning for default form templates like Job Application, Support Ticket, and Wholesale Application, which have file upload fields that are not restricted by design.

Server-side code execution.
Unauthenticated file uploads via forms.
Compromised website integrity.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Sigma Forms Pro WordPress plugin's remote code execution vulnerability necessitates coordination between application owners, infrastructure teams, and potentially vendor management if direct vendor support is required. The immediate priority is to identify all WordPress instances utilizing this plugin, assess their exposure and business criticality, and then plan remediation or apply temporary mitigations to reduce risk.

Application and infrastructure teams own resolution.
Verify plugin use and assess exposure.
Plan remediation based on risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

Free EASM Trial See How Signal Works

Frequently asked questions

What is the Sigma Forms Pro plugin used for?

Sigma Forms Pro is a WordPress plugin designed to handle user-submitted data through custom forms. It is commonly used to build interactive website features like job application portals, customer support ticketing systems, and wholesale inquiry pages, allowing site visitors to submit information and attach files directly to the server.

What does CWE-434 mean regarding CVE-2026-14494?

CWE-434 refers to Unrestricted Upload of File with Dangerous Type. In the context of this CVE, the plugin fails to properly restrict the types of files users can upload. By bypassing security checks and granting excessive permissions during form processing, the software allows attackers to upload executable scripts that the server may then run.

How do attackers trigger this vulnerability?

An attacker triggers this by submitting a specially crafted file through a form managed by the plugin. If a form is configured with an upload field but lacks specific file type restrictions, the plugin may accept malicious code. Importantly, simply having the plugin installed with default templates, such as the Job Application form, provides the necessary path for this action without any prior authentication.

Why is this CVE critical for my website?

Halo Surface Signal notes this vulnerability is particularly significant because it impacts features designed to be public-facing. Since these forms are meant to be accessed by anyone on the internet to submit tickets or applications, the vulnerable entry point is positioned directly on your web server's public edge, making it reachable without needing a user account.

What steps should I take if I use Sigma Forms Pro?

You should immediately inventory your WordPress instances to confirm if this plugin is installed and in use. Evaluate the business criticality of the sites running the plugin and coordinate with your technical teams to plan for updates or mitigations. Until a secure version is verified, consider disabling any forms that utilize file upload fields to prevent unauthorized access.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.