WPMU DEV Dashboard <= 5.0.1 - Authentication Bypass to Administrator via SSO HMAC Canonicalization Confusion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-76581
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 08:16:41 UTC
Updated2026-08-28 20:19:54 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003390000 probability, percentile 0.265950000 (date 2026-08-31)

Problem Types: CWE-347 | CWE-347 CWE-347 Improper Verification of Cryptographic Signature

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Wpmudev WPMU DEV Dashboard affected 5.0.1 semver Not specified

References

ReferenceSourceLinkTags
wpmudev.com/project/wpmu-dev-dashboard [email protected] wpmudev.com
www.wordfence.com/threat-intel/vulnerabilities/id/3d4321c8-15a4-46f5-9b0e-2098a... [email protected] www.wordfence.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Alex Thomas (en)

CNA: Wordfence Argus (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-08-18T00:00:00.000ZDiscovered
CNA2026-08-19T14:21:55.000ZVendor Notified
CNA2026-08-27T17:38:19.000ZDisclosed

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