GHSA-5955-cwv4-h7qh
MEDIUMUmbraco has a Potential Code Execution Risk When Viewing SVG Files in Full Screen in Backoffice
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.
Blast Radius
UmbracoCms.NETUmbraco.Cms.NETUmbraco.CmsReal-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
There is a potential risk of code execution for Backoffice users when they “preview” SVG files in full screen mode.
Workarounds
Server-side file validation is available to strip script tags from file's content during the file upload process.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | UmbracoCms | ≥ 8.0.0&&< 8.18.15 | 8.18.15 |
| .NETNuGet | Umbraco.Cms | ≥ 10.0.0&&< 10.8.7 | 10.8.7 |
| .NETNuGet | Umbraco.Cms | ≥ 13.0.0&&< 13.5.2 | 13.5.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for UmbracoCms. 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 UmbracoCms to 8.18.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5955-cwv4-h7qh 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 GHSA-5955-cwv4-h7qh 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 GHSA-5955-cwv4-h7qh. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-5955-cwv4-h7qh in your dependencies?
O3 detects GHSA-5955-cwv4-h7qh across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.