External risk intelligence

ProSolution WP Client Arbitrary File Upload Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-2942

The vulnerability exists in a WordPress plugin that handles file uploads. WordPress sites and their associated plugins are commonly deployed as public-facing web applications, making this functionality typically accessible over the internet.

Unrestricted File Upload

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

This advisory concerns a critical vulnerability in the ProSolution WP Client WordPress plugin that allows unauthenticated attackers to upload arbitrary files. Such an upload could potentially lead to the execution of malicious code on your website's server. The main concern at this stage is confirming if this plugin is in use within your organization.

Unauthenticated file upload vulnerability exists.
Critical vulnerability could lead to code execution.
Confirm plugin use; assess potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker can upload arbitrary files to a vulnerable WordPress site without authentication. This is possible because the 'proSol_fileUploadProcess' function in the ProSolution WP Client plugin lacks proper file type validation. Successful exploitation could allow an attacker to upload malicious files that enable remote code execution on the server.

No authentication required.
Upload arbitrary files via a function.
Risk of remote code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an unauthenticated attacker to upload arbitrary files to a WordPress site's server. This could potentially lead to the execution of malicious code, impacting the integrity and availability of the website.

Arbitrary files uploaded to the server.
Unauthenticated file upload via a vulnerable function.
Potential for remote code execution on the site.

Operational Fix

Recommended remediation, mitigation, and detection steps

To address this vulnerability, WordPress site administrators and the teams responsible for managing web applications should take the lead. The immediate first step is to identify all WordPress instances utilizing the ProSolution WP Client plugin. Confirming which of these are internet-facing and actively used for critical business functions will prioritize remediation efforts. Subsequently, engaging the accountable owner for each affected site will facilitate planning for the necessary updates or alternative risk-mitigation strategies.

WordPress site administrators and web application owners.
Verify all ProSolution WP Client plugin instances.
Plan remediation or risk mitigation.

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 ProSolution WP Client plugin and how does it function within a WordPress environment?

ProSolution WP Client is an add-on for WordPress websites designed to facilitate client-side interactions. It functions by extending core site capabilities, often managing document exchanges or data uploads through specific internal functions like the proSol_fileUploadProcess, which handles incoming files for site-specific workflows.

How is the vulnerability in CVE-2026-2942 classified in terms of weakness type?

This vulnerability is classified as CWE-434: Unrestricted Upload of File with Dangerous Type. It occurs because the plugin lacks necessary validation mechanisms to verify the content or type of files uploaded, permitting the storage of potentially harmful scripts.

Can the vulnerable file upload function be triggered without administrative authentication?

Yes, the identified flaw resides in the proSol_fileUploadProcess function, which does not require authentication to access. This creates a path for external actors to interact with the plugin directly, though the scope of this vulnerability is limited to the server environment where the plugin is hosted.

Why is the Halo Surface Signal assessment relevant for this plugin vulnerability?

The Halo Surface Signal assigns a score of 4, or Likely, because this plugin is a public-facing component of a WordPress site. Since these applications are frequently exposed to the internet to serve users, the likelihood of an attacker encountering this reachable upload vector remains high.

What initial steps should administrators take to mitigate the risk from this plugin?

Administrators should first perform an inventory to locate all instances of the ProSolution WP Client plugin across their infrastructure. Once identified, prioritize internet-facing sites, confirm usage requirements, and coordinate with site owners to update the software or implement immediate risk-mitigation strategies to prevent unauthorized file storage.

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.