CVE-2026-10522 in MemberHero Plugin
Summary
by MITRE • 08/29/2026
The MemberHero WordPress plugin through 6.9 does not restrict which account fields can be supplied during its frontend registration process, allowing unauthenticated attackers to register a new user with an arbitrary role, including Administrator, leading to a full site takeover.
Version 6.9 is advertised as resolving this issue, but the fix is incomplete and the current version remains exploitable by unauthenticated attackers to obtain administrator access and to take over existing accounts. No version that fully addresses the issue is available at the time of this advisory.
Mitigation: deactivate and remove the MemberHero WordPress plugin through 6.9 until a version that fully resolves this issue is released. If the MemberHero WordPress plugin through 6.9 must stay active, disable public registration, restrict access to the registration functionality, and monitor the site for unexpected administrator accounts.
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Analysis
by VulDB Data Team • 08/29/2026
The vulnerability identified in the MemberHero WordPress plugin prior to version 7.0 represents a critical failure in input validation and authorization logic within the frontend user registration mechanism. This flaw allows unauthenticated attackers to manipulate the account creation process by supplying arbitrary values for role-related fields during submission. In standard web application security models, such as those defined under CWE-269 Improper Privilege Management or CWE-798 Use of Hard-coded Credentials when combined with privilege escalation vectors, sensitive attributes like user roles must be server-side validated and restricted to predefined safe lists. However, in this specific implementation, the plugin fails to enforce these restrictions on the client-facing registration endpoint. Consequently, an attacker can bypass intended access controls by explicitly setting the role parameter to Administrator or other high-privilege levels during the account creation request. This lack of server-side enforcement means that the application trusts user-supplied data for critical security decisions without adequate verification, leading directly to unauthorized privilege escalation.
The operational impact of this vulnerability is severe, resulting in a complete compromise of the targeted WordPress installation. By successfully registering an account with Administrator privileges, an attacker gains full control over the website's backend environment. This level of access permits the modification of site content, injection of malicious code into themes or plugins, and potentially further lateral movement within the hosting infrastructure if additional vulnerabilities exist. Furthermore, because version 6.9 was advertised as resolving this issue but failed to do so completely, existing installations remain vulnerable even after perceived updates. The persistence of this flaw means that attackers can not only create new administrative accounts but also exploit related logic flaws to take over existing user accounts, thereby maintaining persistent access and increasing the difficulty of forensic analysis for site administrators who may assume their systems are secure due to recent patching efforts.
From a threat intelligence perspective, this vulnerability aligns with ATT&CK technique T1078 Valid Accounts, specifically the sub-technique of Initial Access via valid credentials obtained through exploitation of authentication flaws or privilege escalation mechanisms. The ability for an unauthenticated actor to assume administrative privileges effectively bypasses all standard access control layers designed to protect sensitive areas of the application. This scenario highlights a common pitfall in plugin development where frontend interfaces are not adequately synchronized with backend security policies, allowing attackers to exploit trust relationships between client inputs and server-side processing logic. The incomplete fix in version 6.9 underscores the importance of rigorous testing and validation of privilege management controls during software updates, as partial patches may leave critical attack vectors open for exploitation by automated scanning tools or targeted adversaries seeking quick wins against WordPress ecosystems.
To mitigate this risk immediately, it is strongly recommended to deactivate and completely remove the MemberHero plugin from any affected systems running version 6.9 or earlier until a fully patched release becomes available. If business requirements necessitate keeping the plugin active despite its known vulnerabilities, administrators must implement compensating controls by disabling public registration entirely through WordPress settings or via server-side configuration rules that block access to the specific registration endpoints associated with MemberHero. Additionally, restricting access to these functionalities using IP whitelisting can provide an additional layer of defense against unauthenticated exploitation efforts. Continuous monitoring for unexpected administrator accounts and reviewing user role assignments regularly is essential to detect any successful compromises early. Organizations should also consider implementing Web Application Firewall rules that inspect POST requests for suspicious role parameter values during registration attempts, adding a network-level barrier to complement the missing application-layer validation until the vendor releases a definitive fix.