Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Umbraco CMS (NuGet package UmbracoCms.Core) versions 8.0.0 to before 8.18.13, 10.0.0 to before 10.8.4, 12.0.0 to before 12.3.7, and 13.0.0 to before 13.1.1 are affected by stored cross-site scripting through the Markdown editor preview pane on content pages. An attacker with access to the backoffice can store malicious content that is then delivered to the website. Upgrade to 8.18.13, 10.8.4, 12.3.7, or 13.1.1 depending on your major version.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 4.2 | Medium | 3.1 | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0035, the 29th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 21 May 2024, 06:41 UTC Published by the maintainers as a GitHub repository advisory
- 31 Oct 2026, 15:21 UTC First seen by agentprime
- 31 Oct 2026, 15:21 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-gvpc-3pj6-4m9w
- OSV: GHSA-gvpc-3pj6-4m9w
- github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-gvpc-3pj6-4m9w
- nvd.nist.gov/vuln/detail/CVE-2024-35218
- github.com/umbraco/Umbraco-CMS/commit/1b712fe6ec52aa4e71b3acf63e393c8e6ab85385
- github.com/umbraco/Umbraco-CMS/commit/a2684069b1e9976444f60b4b37a80be05b87f6b6
- github.com/umbraco/Umbraco-CMS/commit/cbf9f9bcd199d7ca0412be3071d275556f10b7ba
- github.com/umbraco/Umbraco-CMS/commit/d090176272d07500dac0daee7c598aa8bb321050
- github.com/umbraco/Umbraco-CMS