CVE-2025-24012 is a medium-severity (CVSS 4.6) Cross-site Scripting (XSS) vulnerability in @umbraco-cms/backoffice. O3 Security confirms whether CVE-2025-24012 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Umbraco Backoffice Components Have XSS/HTML Injection Vulnerability
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@umbraco-cms/backofficenpmDescription
Umbraco is a free and open source .NET content management system. Starting in version 14.0.0 and prior to versions 14.3.2 and 15.1.2, authenticated users are able to exploit a cross-site scripting vulnerability when viewing certain localized backoffice components. Versions 14.3.2 and 15.1.2 contain a patch.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @umbraco-cms/backoffice | ≥ 14.0.0&&< 14.3.2 | 14.3.2 |
| 📦npm | @umbraco-cms/backoffice | ≥ 15.0.0&&< 15.1.2 | 15.1.2 |
| .NETNuGet | Umbraco.Cms.StaticAssets | ≥ 14.0.0&&< 14.3.2 | 14.3.2 |
| .NETNuGet | Umbraco.Cms.StaticAssets | ≥ 15.0.0&&< 15.1.2 | 15.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @umbraco-cms/backoffice. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @umbraco-cms/backoffice to 14.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-24012 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 pinpoints whether CVE-2025-24012 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-24012. 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-2025-24012 in your dependencies?
O3 detects CVE-2025-24012 across npm, NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.