CVE-2023-49273 — Umbraco.CMS
MEDIUMCVE-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
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-49273 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
Umbraco.CMS.NETUmbraco.CMS.NETUmbraco.CMSReal-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
Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.8.1, and 12.3.4, users with low privileges (Editor, etc.) are able to access some unintended endpoints. Versions 8.18.10, 10.8.1, and 12.3.4 contain a patch for this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Umbraco.CMS | ≥ 8.0.0&&< 8.18.10 | 8.18.10dotnet add package Umbraco.CMS --version 8.18.10 |
| .NETNuGet | Umbraco.CMS | ≥ 9.0.0&&< 10.8.1 | 10.8.1dotnet add package Umbraco.CMS --version 10.8.1 |
| .NETNuGet | Umbraco.CMS | ≥ 11.0.0&&< 12.3.4 | 12.3.4dotnet add package Umbraco.CMS --version 12.3.4 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-49273 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-49273. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-49273 in your dependencies?
O3 Security finds CVE-2023-49273 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.