dbcve.org
DotnetnukeApplication · Dnnsoftware

CVE-2026-40321

HIGH · 8.0 CVSS v3.1 Published 2026-04-17
Fix available
A fix is available. Upgrade to 10.2.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable

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. Prior to version 10.2.2, a user could upload a specially crafted SVG file that could include scripts that can target both authenticated and unauthenticated DNN users. The impact is increased if the scripts are run by a power user. 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

DNN CMS versions prior to 10.2.2 contain a Cross-Site Scripting (XSS) vulnerability via SVG file upload. Attackers can upload specially crafted SVG files containing malicious scripts that execute in the context of authenticated and unauthenticated users' browsers, with elevated impact when executed by power users.

MitigationUpgrade DNN to version 10.2.2 or later, which patches the SVG file upload vulnerability. Until patched, consider restricting SVG file uploads or implementing content-type validation.

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:< 10.2.2

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
High
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

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. Identify the installed DNN version
    Log into the DNN host or admin dashboard and navigate to About or Site Settings to view the version number. Alternatively, check the web.config file for the version assembly reference or the About page under the Persona Bar menu.
    Affected if The installed version is below 10.2.2 (for example, 10.2.1, 10.1.0, 9.x, or earlier releases).
  2. Confirm SVG file upload functionality is accessible
    Attempt to access the file upload or image upload feature in modules such as File Manager, Image Gallery, or any content module that accepts file attachments. Check if SVG files can be selected and uploaded through the browser interface.
    Affected if SVG files can be successfully uploaded through any DNN module or admin tool.
  3. Review file upload settings and allowed extensions
    Navigate to Host > Host Settings or Site Settings > Site Configuration and locate file type restrictions or upload settings. Check if SVG is listed among allowed file extensions.
    Affected if SVG is explicitly allowed in the permitted file types configuration or no file type restrictions are enforced.
  4. Check for existing SVG files in the portal
    Use the File Manager or navigate to the /Portals/ directory to search for .svg files. Review any previously uploaded SVG content for suspicious script tags or event handlers.
    Affected if SVG files exist in the portal and the DNN version is below 10.2.2.

A DNN installation is affected if it runs a version lower than 10.2.2 and permits SVG file uploads through any accessible module.

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 to version 10.2.2 or later, which patches the SVG file upload vulnerability. Until patched, consider restricting SVG file uploads or implementing content-type validation.

Recommended fix High confidence

DNN version 10.2.2

  1. 1. Back up the existing DNN installation including all website files and the database
  2. 2. Review DNN 10.2.2 release notes and any migration documentation for upgrade requirements
  3. 3. Verify the server meets the system requirements for DNN 10.2.2
  4. 4. Download the DNN 10.2.2 upgrade package from the official DNN community website or GitHub repository
  5. 5. Upload the upgrade files to the server, preserving the site configuration
  6. 6. Run the DNN upgrade process by accessing the website which will trigger the upgrade installer
  7. 7. Follow the upgrade wizard prompts to complete the migration to version 10.2.2
  8. 8. Log in as host/admin and verify the upgrade completed successfully
Caveat Major version upgrades may have breaking changes - test in a staging environment first

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

Fix this in Dotnetnuke Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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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-2026-40321 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