External risk intelligence

Solace Extra WordPress Plugin Data Corruption Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-18316

The vulnerability affects a WordPress plugin, which is an internet-facing web application. WordPress sites are commonly exposed to the public internet to serve content and functionality, making the vulnerable import_zip function reachable to anyone who can interact with the site's AJAX endpoints.

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the Solace Extra WordPress plugin could allow unauthorized users to modify or delete critical site data. This issue stems from a programming oversight that fails to properly check user permissions before allowing certain functions to run, potentially impacting website content and configuration.

Plugin flaw allows data tampering by unauthorized users.
Remember for potential site data loss risks.
Confirm relevance and exposure of this plugin.

Attack Path

How an attacker could exploit the issue

An attacker with basic user access can leverage a flaw in the Solace Extra plugin to modify or delete site content. The vulnerable import_zip function, lacking proper authorization checks, allows any authenticated user to trigger actions like clearing navigation menus, widgets, theme modifications, or importing demo content, potentially leading to data loss.

Any authenticated user can access the function.
The import_zip function lacks a capability check.
Risk of data loss and unauthorized content changes.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow authenticated users, even those with low privileges like Subscribers, to disrupt a WordPress site's functionality and potentially delete or alter critical configurations. Supported conditions include the presence of the Solace Extra plugin and an authenticated user who can access the site's AJAX endpoints.

Site navigation and theme modifications at risk.
Unauthorized modification of WordPress settings.
Disruption of site appearance and content.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the Solace Extra plugin for WordPress affects application owners responsible for managing WordPress sites and their plugins. The first practical step is to identify all WordPress instances using this plugin, confirm their accessibility, and ascertain their business criticality to prioritize remediation efforts.

WordPress application owners should manage this.
Verify plugin reachability and business criticality.
Plan coordinated vendor and internal remediation.

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 Solace Extra plugin used for in WordPress?

Solace Extra is an add-on plugin for WordPress designed to enhance site functionality, often by providing tools for theme customization, layout management, and content organization. It typically acts as a helper component to extend the native capabilities of the WordPress editor and theme system, allowing site administrators to manage complex features like navigation menus, sidebar widgets, and specialized templates more efficiently.

How does CVE-2026-18316 cause data issues?

This vulnerability is classified as Improper Authorization (CWE-862). It occurs because the plugin's import_zip function fails to verify if a user has administrative permissions before executing. Instead of checking for high-level credentials, the plugin relies on a simple security token that is automatically available to everyone, including low-level Subscribers. This allows unauthorized users to command the plugin to delete site data or reset configurations.

Do I need to be an administrator to trigger this bug?

No. You do not need administrative rights to trigger this vulnerability. Any user with a basic, authenticated account on the WordPress site, such as a Subscriber, can invoke the vulnerable function. Note that unauthenticated, anonymous visitors cannot trigger this bug because they lack the session-based access required to interact with the specific AJAX endpoints that the plugin exposes.

Is my site at risk according to Halo Surface Signal?

Yes, your site is considered likely at risk. Halo Surface Signal identifies that because Solace Extra is a plugin for WordPress—an inherently internet-facing web application—the vulnerable AJAX endpoints are generally reachable by anyone who can communicate with your site over the public internet. This exposure means that even low-privileged accounts can potentially alter your site's core settings remotely.

When should I take action for CVE-2026-18316?

You should prioritize action immediately by auditing your WordPress installations to see if the Solace Extra plugin is active. Since this flaw allows unauthorized modification of your menus, theme settings, and widgets, you should assess the business criticality of any site using this plugin and plan to update or remove the component to prevent unauthorized data loss.

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.