ProSolution WP Client <= 2.0.0 - Unauthenticated Arbitrary File Upload via 'files'
Strategic Overview
- Status
- Patched in 2.0.1
- Affected Plugin
- ProSolution WP Client
- Affected Version
<= 2.0.0- CVSS
- 9.8Critical
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2026-6555
At a glance
CVE-2026-6555 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the ProSolution WP Client WordPress plugin, affecting versions <= 2.0.0. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 2.0.1; sites on affected versions should update now. Disclosed May 2026, reported by snr.
Vulnerability Overview
The ProSolution WP Client plugin for WordPress is vulnerable to Arbitrary File Upload in versions up to, and including, 2.0.0. This is due to an array validation mismatch where only the first file in the upload array undergoes extension and MIME type validation, while all files are processed and uploaded to a web-accessible directory. This makes it possible for unauthenticated attackers to upload malicious PHP files and achieve remote code execution by sending a valid first file followed by a malicious file.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-434: Unrestricted Upload of File with Dangerous Type
Reaching this weakness in ProSolution WP Client <= 2.0.0 takes no account at all. An unrestricted file upload lets a caller store a file whose type or destination the application does not properly constrain.
If an uploaded file lands anywhere the server will execute, the flaw becomes remote code execution and the site should be treated as fully compromised. For ProSolution WP Client the fix is 2.0.1: builds <= 2.0.0 are affected, anything from 2.0.1 onward is not.
Remediation
Update to version 2.0.1, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: ProSolution WP Client 2.0.1 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Login Security
External References
Related records
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