CVE-2026-40321 DotNetNuke.Core has stored cross-site-scripting (XSS) via SVG upload

What is CVE-2026-40321?

CVE-2026-40321 is a high-severity cross-site scripting vulnerability in Dnnsoftware Dotnetnuke, published on 17 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

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.

Weakness: CWE-87

Which versions are affected by CVE-2026-40321?

2 open source packages ship an affected version, including DotNetNuke.Core. It affects 1 product.

Products include Dnnsoftware Dotnetnuke.

How do I fix CVE-2026-40321?

Upgrade DotNetNuke.Core to 10.2.2 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-40321 being exploited?

There is no known exploitation of CVE-2026-40321 in the wild and no public exploit code.

Other vulnerabilities in Dnnsoftware Dotnetnuke

• CVE-2017-9822 DotNetNuke (DNN) Remote Code Execution Exploited High 8.8
• CVE-2018-15811 DotNetNuke (DNN) Inadequate Encryption Strength Exploited High 7.5
• CVE-2018-18325 DotNetNuke (DNN) Inadequate Encryption Strength Exploited High 7.5
• CVE-2025-64095 DNN Insufficient Access Control - Image Upload allows for Site Content Overwrite Critical 10.0
• CVE-2006-3601 Privilege escalation in n/a Critical 10.0

All Dnnsoftware Dotnetnuke vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-ffq7-898w-9jc4.