WPMU DEV Dashboard <= 5.0.1 - Authentication Bypass to Administrator via SSO HMAC Canonicalization Confusion
Strategic Overview
- Status
- Patched in 5.0.2
- Affected Plugin
- WPMU DEV Dashboard
- Affected Version
<= 5.0.1- CVSS
- 9.8Critical
- Weakness type
- CWE-347 · Improper Verification of Cryptographic Signature
- CVE
CVE-2026-76581
At a glance
CVE-2026-76581 is a critical-severity Improper Verification of Cryptographic Signature vulnerability in the WPMU DEV Dashboard WordPress plugin, affecting versions <= 5.0.1. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 5.0.2; sites on affected versions should update now. Disclosed August 2026, reported by Alex Thomas.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-347: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
Remediation
Update to version 5.0.2, or a newer patched version
How does WordSec protect against this?
The fix is the thing that ends this: WPMU DEV Dashboard 5.0.2 closes this, and updating the plugin is the step that ends it.
- Alerts
External References
Related records
Other vulnerabilities in WPMU DEV Dashboard
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