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.NET
.NET NuGet
Not in CISA KEV
LOW severity

CVE-2023-49279 — Umbraco.CMS

LOW

CVE-2023-49279 is a low-severity (CVSS 3.7) Cross-site Scripting (XSS) vulnerability in Umbraco.CMS. A fix is available for Umbraco.CMS — see the affected versions and patch details below.

Umbraco CMS vulnerable to stored XSS via SVG File Upload

Also known asGHSA-6xmx-85x3-4cv2
Published
Updated
Affected
5 pkgs
Patched
5 / 5
Exploits
None indexed
Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-49279.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk
0.00%0.32%0.63%0.95%0.4%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

5 pkgs affected
.NETUmbraco.CMS.NETUmbraco.CMS.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

Umbraco is an ASP.NET content management system (CMS). Starting in version 7.0.0 and prior to versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0, a user with access to the backoffice can upload SVG files that include scripts. If the user can trick another user to load the media directly in a browser, the scripts can be executed. Versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0 contain a patch for this issue. Some workarounds are available. Implement the server side file validation or serve all media from an different host (e.g cdn) than where Umbraco is hosted.

Affected Packages

5 total 5 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetUmbraco.CMS≥ 7.0.0&&< 7.15.117.15.11dotnet add package Umbraco.CMS --version 7.15.11
.NETNuGetUmbraco.CMS≥ 8.0.0&&< 8.18.98.18.9dotnet add package Umbraco.CMS --version 8.18.9
.NETNuGetUmbraco.CMS≥ 9.0.0&&< 10.7.010.7.0dotnet add package Umbraco.CMS --version 10.7.0
.NETNuGetUmbraco.CMS≥ 11.0.0&&< 11.5.011.5.0dotnet add package Umbraco.CMS --version 11.5.0
.NETNuGetUmbraco.CMS≥ 12.0.0&&< 12.2.012.2.0dotnet add package Umbraco.CMS --version 12.2.0

Affected Products

1 product · 5 configurations
Application
umbraco cmsumbraco
≥ 12.0.0 && < 12.2.0
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 7.15.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49279 is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

Umbraco is an ASP.NET content management system (CMS). Starting in version 7.0.0 and prior to versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0, a user with access to the backoffice can upload SVG files that include scripts. If the user can trick another user to load the media directly in a browser, the scripts can be executed. Versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0 contain a patch for this issue. Some workarounds are available. Implement the server side file validation or serve all media from an different host (e.g cdn) than where Umbraco is hosted.
O3 Security · Impact-Aware SCA

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CVE-2023-49279: Umbraco.CMS — Fixed in 7.15.11