CVE-2026-31832 is a medium-severity security vulnerability in Umbraco.Cms (nuget), affecting versions >= 14.0.0, < 16.5.1. It is fixed in 16.5.1, 17.2.2.
Description A broken object-level authorization vulnerability exists in a backoffice API endpoint that allows authenticated users to assign domain-related data to content nodes without proper authorization checks. The issue is caused by insufficient authorization enforcement on the affected API endpoint, whereby via an API call, domains can be set on content nodes that the editor does not have permission to access (either via user group privileges or start nodes). Impact An attacker can modify domain configurations for content nodes they are not permitted to edit. This may result in malicious or unintended routing behaviour, service disruption, and potential disclosure of configuration-related information. Patches The issue is patched in 16.5.1 and 17.2.2. Workarounds There is no workaround other than upgrading.
CVE-2026-31832 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (16.5.1, 17.2.2). Upgrading removes the vulnerable code path.
nuget
Umbraco.Cms (>= 14.0.0, < 16.5.1)Umbraco.Cms (>= 17.0.0, < 17.2.2)Umbraco.Cms → 16.5.1 (nuget)Umbraco.Cms → 17.2.2 (nuget)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-31832 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-31832 is reachable in your applications. Get a demo
Upgrade the following packages to resolve this vulnerability:
Umbraco.Cms to 16.5.1 or laterUmbraco.Cms to 17.2.2 or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-31832 is a medium-severity security vulnerability in Umbraco.Cms (nuget), affecting versions >= 14.0.0, < 16.5.1. It is fixed in 16.5.1, 17.2.2.
CVE-2026-31832 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Umbraco.Cms (nuget) versions >= 14.0.0, < 16.5.1 is affected.
Yes. CVE-2026-31832 is fixed in 16.5.1, 17.2.2. Upgrade to this version or later.
Whether CVE-2026-31832 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Umbraco.Cms to 16.5.1 or laterUmbraco.Cms to 17.2.2 or later