CVE-2020-29454 is a medium-severity (CVSS 4.3) CWE-863 vulnerability in UmbracoCms. A fix is available for UmbracoCms — see the affected versions and patch details below.
Incorrect permission enforcement in UmbracoCms
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
UmbracoCmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Editors/LogViewerController.cs in Umbraco through 8.9.1 allows a user to visit a logviewer endpoint even if they lack Applications.Settings access.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | UmbracoCms | all versions | 8.10.0dotnet add package UmbracoCms --version 8.10.0 |
Affected Products
umbraco cmsumbracoDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for UmbracoCms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update UmbracoCms to 8.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-29454 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2020-29454 in your dependencies?
Find it across NuGet, including transitive dependencies.