External risk intelligence

Gardyn Cloud API Unauthenticated User Data Exposure

CVE advisorySeverity: CRITICAL (CVSS 9.2)

CVE-2026-28766

The vulnerability exists in a cloud API endpoint that is public-facing by design, as it serves registered users of the service via the internet. Because it provides direct, unauthenticated access to user account information, it functions as an exposed internet service in its normal, intended operational state.

Missing Authentication

Mygardyn Cloud Api

before 2.12.2026

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 vulnerability has been identified in a cloud API affecting Gardyn user accounts, allowing unauthorized access to all registered user information without authentication. This presents a potential risk to user data privacy and system integrity. The main concern at this time is confirming relevance and exposure.

Unauthenticated access to user account information.
Matters for user data privacy and trust.
Confirm relevance and scope of impact.

Attack Path

How an attacker could exploit the issue

An attacker could access a specific unauthenticated endpoint to retrieve all user account information for registered Gardyn users. This exposure could potentially lead to unauthorized access to sensitive personal data.

No authentication needed to access.
Endpoint exposes all user account data.
Risk of unauthorized data access.

Live Threat

Current exploitation, exposure, and threat context

A specific endpoint exposes all registered user account information without authentication. This could affect system data and sensitive user information when supported by the advisory.

User account information could be exposed.
Access is available via an unauthenticated endpoint.
Unauthorized access to user data.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the mygardyn cloud API likely falls under the responsibility of the platform or cloud infrastructure team, given its public-facing nature. The first practical step is to identify all instances of the affected API, determine its exposure and business criticality, and then coordinate with the vendor for remediation.

Platform or cloud team owns remediation.
Verify API reachability and criticality.
Coordinate vendor-provided fix.

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.

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Frequently asked questions

What is the Gardyn cloud_api?

The Gardyn cloud_api is the backend infrastructure that manages communication between Gardyn devices—often used for automated indoor gardening—and the cloud. It handles data synchronization, user account management, and service operations, acting as the bridge that allows users to monitor and control their systems remotely through the internet.

What is the weakness in CVE-2026-28766?

This vulnerability is classified as CWE-306, which refers to a Missing Authentication for Critical Function. In plain terms, the software fails to verify the identity of someone requesting information. Because this security check is absent, the affected API endpoint permits anyone to query and retrieve private user account information without proving they have authorized access to that data.

How does an attacker trigger CVE-2026-28766?

An attacker can trigger this vulnerability by sending a standard request to the specific, unprotected API endpoint identified in the advisory. No special preconditions, elevated privileges, or complex exploit chains are required; the system simply delivers the data because it is not configured to require authentication. Accessing the system through standard, authenticated channels does not trigger this; the issue lies specifically with the exposed, unauthenticated endpoint.

Why is this CVE considered relevant?

According to Halo Surface Signal, this vulnerability is highly relevant because the cloud API is public-facing by design to support registered users over the internet. Since the endpoint remains accessible to anyone on the web and provides direct access to sensitive user account information without any verification, it creates a significant privacy risk in its normal operational state.

What should I do if I use this technology?

Because this involves a cloud-based service, the remediation is managed by the vendor. Your first practical step is to verify if your specific environment relies on the affected version of the cloud_api. If so, monitor official vendor communications for updates, as the provider is responsible for applying the necessary security patches to the backend endpoint to enforce proper authentication.

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.