What is CVE-2026-40321?

CVE-2026-40321 is a high-severity vulnerability in Dnnsoftware Dnn.platform, classified under Improper Neutralization of Alternate XSS Syntax. CVSS score: 8.1/10. Published 2026-04-17.

How severe is CVE-2026-40321?

High severity. CVSS v3 base score is 8.1 out of 10.

XSS in Dnnsoftware Dnn.platform

CVE-2026-40321

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 authent…

EPSS: 0.000 (6.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H.

Affected products

Dnnsoftware Dnn.platform — versions < 10.2.2

Weakness classification (CWE)

CWE-87 — Improper Neutralization of Alternate XSS Syntax

References

https://github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-ffq7-898w-9jc4 (x_refsource_CONFIRM)
https://github.com/dnnsoftware/Dnn.Platform/releases/tag/v10.2.2 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-40321?: CVE-2026-40321 is a high-severity vulnerability in Dnnsoftware Dnn.platform, classified under Improper Neutralization of Alternate XSS Syntax. CVSS score: 8.1/10. Published 2026-04-17.
How severe is CVE-2026-40321?: High severity. CVSS v3 base score is 8.1 out of 10.