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.NET
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Not in CISA KEV
MEDIUM severity

CVE-2023-49273 — Umbraco.CMS

MEDIUM

CVE-2023-49273 is a medium-severity (CVSS 5.4) CWE-863 vulnerability in Umbraco.CMS. A fix is available for Umbraco.CMS — see the affected versions and patch details below.

Umbraco CMS vulnerable to Privilege Escalation using Spoofing

Also known asGHSA-cfr5-7p54-4qg8
Published
Updated
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs31th percentile — riskier than 31% of all scored CVEsHighest risk
0.00%0.29%0.58%0.87%0.3%0.4%May 26Sep 26Nov 26

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

3 pkgs affected
.NETUmbraco.CMS.NETUmbraco.CMS.NETUmbraco.CMS

Real-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

Impact

Users with low privileges ( Editor, etc) are able to access some unintended endpoints.

Explanation of the vulnerability

Possible to delete redirect urls, when disabled by admin with only access to backoffice Possible to access the examine dashboard with only access to backoffice Possible to access the published cache dashboard with only access to backoffice Possible to access the telemetry dashboard with only access to backoffice Possible to access the languages with only access to backoffice Possible to access the stylesheets with only access to backoffice

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetUmbraco.CMS≥ 8.0.0&&< 8.18.108.18.10dotnet add package Umbraco.CMS --version 8.18.10
.NETNuGetUmbraco.CMS≥ 9.0.0&&< 10.8.110.8.1dotnet add package Umbraco.CMS --version 10.8.1
.NETNuGetUmbraco.CMS≥ 11.0.0&&< 12.3.412.3.4dotnet add package Umbraco.CMS --version 12.3.4

Affected Products

1 product · 3 configurations
Application
umbraco cmsumbraco
≥ 12.0.0 && < 12.3.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.CMS, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Umbraco.CMS to 8.18.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49273 is resolved across your whole dependency graph.

  3. 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

#### Impact Users with low privileges ( Editor, etc) are able to access some unintended endpoints. #### Explanation of the vulnerability Possible to delete redirect urls, when disabled by admin with only access to backoffice Possible to access the examine dashboard with only access to backoffice Possible to access the published cache dashboard with only access to backoffice Possible to access the telemetry dashboard with only access to backoffice Possible to access the languages with only access to backoffice Possible to access the stylesheets with only access to backoffice
O3 Security · Impact-Aware SCA

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CVE-2023-49273: Umbraco.CMS — Fixed in 8.18.10