Cyber Resilience

CVE-2026-6555

Critical

Published: 20 May 2026

Published
20 May 2026
Modified
20 May 2026
KEV Added
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Patch
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CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0098 57.8th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-6555 is a critical-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Wordpress (inferred from references). Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 42.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A06:2025 Insecure Design

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)
CWE-434

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
attack.mitre.org →
T1105 Ingress Tool Transfer Command And Control
Adversaries may transfer tools or other files from an external system into a compromised environment.
attack.mitre.org →
Why these techniques?

Arbitrary file upload in public-facing WP plugin enables unauthenticated web shell upload (T1190 + T1505.003) and tool transfer (T1105) for RCE.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2025-26325Shared CWE-434
CVE-2025-66256Shared CWE-434
CVE-2025-1025Shared CWE-434
CVE-2016-15043Shared CWE-434
CVE-2024-13448Shared CWE-434
CVE-2024-13333Shared CWE-434
CVE-2013-10040Shared CWE-434
CVE-2026-32523Shared CWE-434
CVE-2025-6423Shared CWE-434
CVE-2025-7063Shared CWE-434

Affected Assets

Wordpress
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inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

MP-7 Media Use
addresses: CWE-434

Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.

SC-44 Detonation Chambers
addresses: CWE-434

Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.

SC-51 Hardware-based Protection
addresses: CWE-434

Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.

SI-3 Malicious Code Protection
addresses: CWE-434

Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.

References