CVE-2026-76581Network attack vector

Administrator session takeover via ambiguous SSO HMAC

Published Aug 28, 2026 · Updated Aug 28, 2026

Authentication bypass in WPMU DEV Dashboard 5.0.1 and earlier allows remote attackers to obtain a WordPress administrator session. The wdpsso_step1 action signs and discloses an unseparated token, state, redirect, and domain string, while wdpsso_step2 verifies an unseparated string that omits domain, allowing field-boundary confusion and HMAC replay. Exploitation requires a site connected to WPMU DEV with Hub SSO enabled and mapped to an administrator account.

CVSS severity9.8
Critical
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in WPMU DEV Dashboard 5.0.1 and earlier allows remote attackers to obtain a WordPress administrator session. The wdpsso_step1 action signs and discloses an unseparated token, state, redirect, and domain string, while wdpsso_step2 verifies an unseparated string that omits domain, allowing field-boundary confusion and HMAC replay. Exploitation requires a site connected to WPMU DEV with Hub SSO enabled and mapped to an administrator account.

The record

CVE
CVE-2026-76581
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
WPMU DEV
Product
WPMU DEV Dashboard
Classifications
CWE-347, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=5.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPMU DEV · WPMU DEV Dashboardversion=0 <=5.0.1

Published CVSS scores

9.8WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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