CVE-2026-31833: Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering

CVE-2026-31833 · Severity: low · CVSS 3.1 · Published 2026-03-11

Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering

Technologies: Umbraco.Cms (NuGet). Vendors: NuGet.

Quick answers

Is CVE-2026-31833 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-31833 being exploited in the wild.
How severe is CVE-2026-31833?
Low severity, with a CVSS score of 3.1, published 11 March 2026.
Which products and versions are affected?
Umbraco.Cms (NuGet) ECOSYSTEM:introduced=16.2.0,fixed=16.5.1.
Is there a fix for CVE-2026-31833?
Yes. Umbraco.Cms (NuGet): upgrade to 16.5.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-31833?
Check whether you run Umbraco.Cms (NuGet) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Umbraco.Cms (NuGet): upgrade to 16.5.1 or later
    dotnet add package Umbraco.Cms --version 16.5.1

Affected products

  • Umbraco.Cms (NuGet) ECOSYSTEM:introduced=16.2.0,fixed=16.5.1

Identifiers

  • CVE-2026-31833
  • GHSA-vrqc-59mw-qqg7

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