GHSA-rhcg-3h8r-v6vp
HIGHUmbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
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
Umbraco.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
Description
A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships.
The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles.
Impact
An authenticated backoffice user may be able to escalate their privileges to Administrator level.
Successful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and configuration settings.
The impact is significantly mitigated by the fact that this can only be exploited by a user that has already been given access to the "Users" section in the CMS. For most Umbraco setups, such users are already also "Administrators".
Patches
The issue is patched in 16.5.1 and 17.2.2.
Workarounds
There is no workaround other than upgrading for setups where they want to have users with permission for the "Users" section without also being content with those users also being part of the "Administrators" user group.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Umbraco.Cms | ≥ 15.3.1&&< 16.5.1 | 16.5.1 |
| .NETNuGet | Umbraco.Cms | ≥ 17.0.0&&< 17.2.2 | 17.2.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.Cms. 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 to 16.5.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rhcg-3h8r-v6vp 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-rhcg-3h8r-v6vp 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-rhcg-3h8r-v6vp. 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-rhcg-3h8r-v6vp in your dependencies?
O3 detects GHSA-rhcg-3h8r-v6vp across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.