What is CVE-2026-76581?
The WPMU DEV Dashboard plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.0.1. This is due to inconsistent and ambiguous HMAC message construction between the unauthenticated `wdpsso_step1` and `wdpsso_step2` AJAX actions, where step 1 signs and discloses an unseparated concatenation of the token, state, redirect, and domain values, while step 2 verifies an unseparated concatenation that omits the domain field. This makes it possible for unauthenticated attackers, on sites connected to WPMU DEV with Hub SSO enabled and mapped to an administrator, to obtain a valid HMAC from step 1 and replay it to step 2 by moving the domain value into the redirect field, resulting in an authenticated administrator session.
Affected product
See advisory
Remediation Steps
- Update all affected WordPress plugins to patched versions
- Review admin account login logs for unauthorized access
- Audit user roles and permissions for unexpected changes
- Consider temporary deactivation of vulnerable plugins if immediate patch is unavailable
References
Referenced in our briefings & reports
- Vulnerability Priority Report – Week 4 of August 2026 (August 24 – 30)
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