CVE-2026-76581 WPMU DEV Dashboard <= 5.0.1 - Authentication Bypass to Administrator via SSO HMAC Canonicalization Confusion
Unauthenticated attackers can bypass authentication to gain administrator access via HMAC confusion in WPMU DEV Dashboard when Hub SSO is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76581?
CVE-2026-76581 is a critical authentication bypass vulnerability in wpmudev WPMU DEV Dashboard, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-347
Which versions are affected by CVE-2026-76581?
How do I fix CVE-2026-76581?
No fix has been published for CVE-2026-76581 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-76581 being exploited?
There is no known exploitation of CVE-2026-76581 in the wild and no public exploit code.
Public exploit code: 2 proofs of concept on GitHub.
Sources
Also known as GHSA-2cxw-5886-mfv5.