CVE-2026-6555

CVE-2026-6555 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-434.

Key facts

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.

Frequently asked questions

What is CVE-2026-6555?
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.
How severe is CVE-2026-6555?
CVE-2026-6555 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-6555 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-6555?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-6555 have an EU (EUVD) identifier?
Yes. CVE-2026-6555 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31016.
When was CVE-2026-6555 published?
CVE-2026-6555 was published on 2026-05-20 and last updated on 2026-06-23.

References

Other CWE-434 (Unrestricted Upload of File with Dangerous Type) vulnerabilities

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