dbcve.org
DotnetnukeApplication · Dnnsoftware

CVE-2026-40306

MEDIUM · 6.5 CVSS v3.1 Published 2026-04-17
Fix available
A fix is available. Upgrade to 10.2.2 or later.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. All new installations of DNN 10.x.x - 10.2.1 have the same Host GUID. This does not affect upgrades from 9.x.x. Version 10.2.2 patches the issue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

All new DNN 10.x.x through 10.2.1 installations ship with an identical Host GUID, a unique identifier that should be distinct for each installation. This predictable identifier could enable authentication bypass, session hijacking, or other GUID-dependent security controls to be circumvented across affected installations.

MitigationUpgrade DNN installations to version 10.2.2 or later, which generates a unique Host GUID for new installations. Upgrades from 9.x.x are unaffected.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
DotnetnukeApplication
Affected:>= 10.0.0, < 10.2.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify DNN version is within affected range
    Check the installed DNN version through the admin dashboard (Site Settings > Dashboard) or by inspecting the web.config file for the version number
    Affected if Version is 10.0.0 through 10.2.1 (excluding 10.2.2 and later) AND this is a fresh installation, not an upgrade from 9.x.x
  2. Confirm installation type
    Determine whether this is a fresh 10.x installation or an upgrade from a 9.x version by checking the installation history or database upgrade logs
    Affected if The installation is a fresh 10.x.x install rather than an upgrade from 9.x.x (upgrades are unaffected)
  3. Locate the Host GUID
    Access the Host settings in the DNN admin panel or query the database (typically found in the HostSettings or similar configuration table) for the Host GUID value
    Affected if The Host GUID cannot be located or retrieved from the expected configuration location
  4. Compare Host GUID against known default
    Examine the Host GUID value stored in the DNN configuration or database. If multiple independent 10.x.x installations exist, compare GUIDs between them to detect if they share the same value
    Affected if The Host GUID matches the known default GUID shipped with 10.x.x installations, or matches the GUID found in other independent DNN installations (indicating non-unique value)

A user is affected if they are running a fresh DNN 10.0.0-10.2.1 installation (not upgraded from 9.x) where the Host GUID matches the default value shared across all such installations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.2.2 or later
Fixed in 10.2.2
Interim mitigation

Upgrade DNN installations to version 10.2.2 or later, which generates a unique Host GUID for new installations. Upgrades from 9.x.x are unaffected.

Recommended fix High confidence

10.2.2

  1. 1. Back up the existing DNN database and application files
  2. 2. Download DNN version 10.2.2 or later from the official DNN repository
  3. 3. Extract the upgrade package and follow DNN's standard upgrade procedure
  4. 4. Run the upgrade installation to replace the duplicate Host GUID with a unique one
  5. 5. Verify the upgrade completed successfully and test the application
Caveat Standard DNN upgrade considerations apply; new installations get a unique Host GUID after upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dotnetnuke Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40306 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data