CVE-2024-35239 — Umbraco.Forms
LOWCVE-2024-35239 is a low-severity (CVSS 2.7) vulnerability in Umbraco.Forms. A fix is available for Umbraco.Forms — see the affected versions and patch details below.
Umbraco Forms components vulnerable to Stored Cross-site Scripting
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-2024-35239.
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-2024-35239 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.Forms.NETUmbraco.Forms.NETUmbraco.Forms.NETUmbraco.FormsReal-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
Impact
Authenticated user that has access to edit Forms may inject unsafe code into Forms components.
Patches
Issue can be mitigated by configuring TitleAndDescription:AllowUnsafeHtmlRendering after upgrading to patched versions (13.0.1, 12.2.2, 10.5.3, 8.13.13).
References
https://docs.umbraco.com/umbraco-forms/release-notes#id-13.0.1-january-16th-2024 https://docs.umbraco.com/umbraco-forms/v/12.forms.latest/release-notes#id-12.2.2-january-16th-2024 https://docs.umbraco.com/umbraco-forms/v/10.forms.latest/release-notes https://docs.umbraco.com/umbraco-forms/developer/configuration#editing-configuration-values
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Umbraco.Forms | ≥ 13.0.0&&< 13.0.1 | 13.0.1dotnet add package Umbraco.Forms --version 13.0.1 |
| .NETNuGet | Umbraco.Forms | ≥ 12.0.0&&< 12.2.2 | 12.2.2dotnet add package Umbraco.Forms --version 12.2.2 |
| .NETNuGet | Umbraco.Forms | ≥ 10.0.0&&< 10.5.3 | 10.5.3dotnet add package Umbraco.Forms --version 10.5.3 |
| .NETNuGet | Umbraco.Forms | ≥ 8.0.0&&< 8.13.13 | 8.13.13dotnet add package Umbraco.Forms --version 8.13.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.Forms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Umbraco.Forms to 13.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-35239 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-2024-35239 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-35239. 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-2024-35239 in your dependencies?
O3 Security finds CVE-2024-35239 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.