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

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.

Published: 2026-05-20 Last update: 2026-05-20 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-6555 is rated Moderate Risk (59.6/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.95%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-6555

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.35% 0.95% +0.60%
2 2026-05-26 0.27% 0.35% +0.09%
3 2026-05-20 0.27%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6555

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 5.9 [email protected]

Weakness enumeration for CVE-2026-6555

GitHub Security Advisory for CVE-2026-6555

GHSA-pwg9-vp4w-mc97 · Severity: critical — The ProSolution WP Client plugin for WordPress is vulnerable to Arbitrary File Upload in versions...

Affected software / configurations for CVE-2026-6555

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-6555

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