Vulnerability · Published Aug 28, 2026 · Assigned by Wordfence
CVE-2026-76581WPMU DEV Dashboard <= 5.0.1 - Authentication Bypass to Administrator via SSO HMAC Canonicalization Confusion
Critical 9.8
In plain English
A critical-severity security flaw in WPMU DEV Dashboard from wpmudev. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
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 products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| wpmudev | WPMU DEV Dashboard | 0 – through 5.0.1 |
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H