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CVE Record

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

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.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A flaw in WPMU DEV Dashboard through version 5.0.1 may let an unauthenticated internet attacker obtain a WordPress administrator session. Exposure requires the site to be connected to WPMU DEV, have Hub SSO enabled, and map that SSO access to an administrator. Successful abuse could permit complete site compromise.

Executive priority

Act immediately on internet-facing sites meeting all exposure conditions. The potential outcome is unauthenticated administrator takeover with confidentiality, integrity, and availability impact. Accelerate inventory and vendor-guidance review today; prioritize remediation over routine maintenance. Sites without the plugin or required Hub SSO configuration are not shown by the supplied evidence to be exploitable through this flaw.

Technical view

The two unauthenticated SSO AJAX actions construct HMAC messages inconsistently. Step 1 signs and reveals an ambiguous concatenation containing token, state, redirect, and domain; step 2 verifies a concatenation omitting domain. An attacker may reuse a valid signature across these interpretations and receive an administrator session. The issue is classified as CWE-347 and CVSS 3.1 9.8.

Likely exposure

Prioritize WordPress sites running WPMU DEV Dashboard 5.0.1 or earlier. Practical exposure is conditional: the site must be connected to WPMU DEV, Hub SSO must be enabled, and its mapping must provide administrator access. The supplied affected-product metadata is inconsistent, so confirm inventory against current vendor guidance.

Exploitation context

The CVSS vector describes remote, low-complexity exploitation requiring neither credentials nor user interaction. However, the supplied record is not marked as CISA KEV, and the source bundle provides no evidence of exploitation in the wild. Treat the attack path as plausible and severe, but do not report active exploitation as established.

Researcher notes

The core weakness is ambiguous, delimiter-free HMAC canonicalization combined with disagreement over included fields. Assessment should focus on configuration prerequisites and evidence of abnormal SSO-to-admin session creation. No exploit testing is necessary for initial triage. The bundle names no fixed version or official mitigation and contains inconsistent affected-version metadata, limiting remediation certainty.

Mitigation direction

  • Inventory every WordPress site running WPMU DEV Dashboard and record its installed version.
  • Identify sites connected to WPMU DEV with Hub SSO enabled and administrator mapping.
  • Check WPMU DEV and Wordfence guidance for a confirmed patched release or supported mitigation.
  • Apply the vendor-confirmed update or mitigation as soon as it becomes available.
  • Review privileged accounts and sessions on exposed sites; investigate unexpected administrator access.

Validation and detection

  • Confirm the plugin version directly on each WordPress installation.
  • Verify whether WPMU DEV connectivity, Hub SSO, and administrator mapping are enabled.
  • Compare installed versions with the latest vendor and Wordfence advisories.
  • Review logs for unusual SSO AJAX activity followed by unexpected administrator sessions.
  • After remediation, confirm the vendor-approved version or configuration is consistently deployed.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-347: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-76581 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
6Timeline events
1ADP providers
3Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Wordfence

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2026-76581Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineWordfence

    Discovered

  2. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  3. Source timelineWordfence

    Vendor Notified

  4. Source timelineWordfence

    Disclosed

  5. CVE publishedCVE Program

    The CVE record was published.

  6. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
wpmudevWPMU DEV Dashboard0unaffected
Weakness

CWE details

CWE-347

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-347 · source CWE mapping

CWE mapping pending import

This CVE carries a CWE mapping that will resolve to a full Glexia CWE intelligence page after the official CWE import is complete.

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