WordPress Ultimate Member Plugin Allows Unauthenticated Admin Registration

The Ultimate Member WordPress plugin before 2.12.1 does not filter administrator-level capabilities from the roles it makes selectable on its registration forms, and its post-registration safeguard against elevated accounts is disabled by default, allowing unauthenticated users to register with a site-defined role that carries administrator capabilities and gain administrative access, when such a role exists and a role-selection field is present on a published registration form.

Casky was already ahead

This CVE exploits attack patterns that Casky's 224matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The Ultimate Member WordPress plugin before version 2.12.1 contains a critical privilege escalation vulnerability that allows unauthenticated users to register with administrator-level capabilities. The plugin fails to properly filter administrative roles from its registration form role-selection fields, and its post-registration safeguard against privilege elevation is disabled by default. This means any visitor to a WordPress site using this plugin can bypass authentication entirely and gain full administrative access, provided a custom role with admin capabilities exists and is exposed on a published registration form. Website administrators using this plugin are at immediate risk of complete account takeover and site compromise.

Casky's 224 mapped security skills detect the attack patterns underlying this vulnerability through Claude AI's extended reasoning across MITRE ATT&CK technique TA0004 (Privilege Escalation). Practitioners using the platform would observe detection findings focused on improper input validation during account creation, unauthorized capability assignment in user registration workflows, and role-based access control bypass patterns. The skills would flag suspicious registration events where unauthenticated users suddenly acquire high-privilege roles, identify missing validation logic that should filter administrative capabilities, and correlate post-registration account state changes that deviate from expected user roles. Security teams would see these indicators cluster around registration endpoints, revealing the exploitation chain from anonymous access through privilege escalation to administrative account creation.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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224 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-12251.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

penetration testing · medium

Run

MITRE ATT&CK Techniques

TA0004

Investigate the attack patterns behind CVE-2026-12251

Casky has 224 skills that investigate the attack patterns behind CVE-2026-12251. Run one and get CVSS-scored findings in 3 minutes.

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