External risk intelligence

Joomla Fabrik PHP Element Unauthenticated Code Execution

CVE advisorySeverity: CRITICAL (CVSS 10.0)

CVE-2026-76604

The vulnerability exists in a Joomla extension designed to handle web forms. Because these forms are typically exposed on public-facing websites to collect user input, the vulnerable component is directly reachable by internet users by design.

Code Injection

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

This vulnerability impacts a Joomla extension that processes web forms. An unauthenticated attacker could potentially execute arbitrary code on affected systems. The primary concern is to confirm if this extension is in use and exposed to external access.

Code execution vulnerability in a web form tool.
Matters if your organization uses this specific Joomla extension.
Confirm relevance and exposure for potential risk.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted input to a vulnerable Joomla extension that processes PHP code within forms. This could occur through a public-facing website, potentially leading to severe compromise of the server.

No authentication or privileges needed.
Submitting data to a PHP form element.
Full server compromise is possible.

Live Threat

Current exploitation, exposure, and threat context

The PHP form element in this Joomla extension could allow an unauthenticated attacker to execute arbitrary code. This could impact the integrity and availability of the affected system, potentially leading to unauthorized actions or disruption of service when the extension is used to process user-submitted data.

System code and service integrity at risk.
Remote code execution via vulnerable form element.
Unauthorized system control or service disruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and infrastructure teams are likely responsible for addressing this critical vulnerability in Joomla extensions. The first practical step involves identifying all instances of the affected extension, confirming their reachability and business criticality, and then locating the accountable owner to plan remediation based on the identified risk.

Application owners should address this.
Verify unauthenticated remote code execution exposure.
Plan remediation based on asset criticality.

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 Fabrik extension for Joomla?

Fabrik is a powerful, flexible component for the Joomla content management system that allows users to build custom data-driven applications. It is frequently used to create complex web forms, manage database records, and display data through visualizations, effectively turning a standard website into a functional web application.

What does CWE-94 mean for CVE-2026-76604?

CWE-94 refers to improper control of generation of code. In the context of this vulnerability, it means the extension fails to safely handle input provided to its PHP form elements. Because it does not properly restrict or sanitize this input, an attacker can supply malicious instructions that the server executes as if they were legitimate system commands.

How is this Fabrik vulnerability triggered?

An attacker triggers this flaw by submitting specially crafted input to a vulnerable PHP form element within the Fabrik extension. Crucially, the system does not require the attacker to have an account or any special permissions to do this. Simply interacting with the form's data input mechanism is enough to initiate the execution of unauthorized code.

Why does Halo Surface Signal categorize this as external?

Halo Surface Signal labels this as external because Fabrik is designed specifically to handle web forms intended for public interaction. Since these forms are typically placed on internet-facing pages to gather information from visitors, the vulnerable code is directly reachable by anyone on the internet without needing access to your internal network.

What is the first step to address this issue?

You should immediately inventory your Joomla environments to determine if the Fabrik extension is installed and if you are running a version earlier than 4.7.3. Once identified, locate the business owner of each site to assess the risk and coordinate a path toward updating the software or disabling the affected form elements to prevent unauthorized access.

References

www.fabrikar.com/

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.