# CVE-2026-31832: Umbraco Backoffice API Allows Unauthorized Modification of Domain Data

> Authenticated users can modify domain data on unauthorized content nodes due to missing authorization checks in the Umbraco backoffice API.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Mar 2026
- **Updated:** 11 Mar 2026
- **Also known as:** GHSA-fpvf-fvp5-996r

## What is CVE-2026-31832?

CVE-2026-31832 is a medium-severity missing authorization vulnerability in Umbraco Umbraco Cms, published on 10 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Umbraco is an ASP.NET CMS. From 14.0.0 to before 16.5.1 and 17.2.2, 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). This vulnerability is fixed in 16.5.1 and 17.2.2.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-31832?

4 open source packages ship an affected version, including Umbraco.Cms. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Umbraco.Cms` | NuGet | From 14.0.0 | 16.5.1 |
| `Umbraco.Cms` | NuGet | From 14.0.0 | 16.5.1 |
| `Umbraco.Cms` | NuGet | From 17.0.0 | 17.2.2 |
| `Umbraco.Cms` | NuGet | From 17.0.0 | 17.2.2 |

Products: Umbraco Umbraco Cms.

## How do I fix CVE-2026-31832?

Upgrade Umbraco.Cms to a fixed version for your release line: 16.5.1 or 17.2.2.

## Is CVE-2026-31832 being exploited?

There is no known exploitation of CVE-2026-31832 in the wild and no public exploit code.

## Other vulnerabilities in Umbraco Umbraco Cms

- [CVE-2025-67288](https://insights.sbomify.com/CVE-2025-67288/): Umbraco CMS has an arbitrary file upload vulnerability (critical 10.0)
- [CVE-2014-10074](https://insights.sbomify.com/CVE-2014-10074/): File upload in n/a (critical 9.8)
- [CVE-2012-1301](https://insights.sbomify.com/CVE-2012-1301/): Server-side request forgery in n/a (critical 9.8)
- [CVE-2012-10054](https://insights.sbomify.com/CVE-2012-10054/): Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE (critical 9.3)
- [CVE-2025-32017](https://insights.sbomify.com/CVE-2025-32017/): Umbraco has a Management API Vulnerability to Path Traversal With Authenticated Users (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31832 and fix it if it is affected.

What it is: CVE-2026-31832 is a medium-severity missing authorization vulnerability in Umbraco Umbraco Cms, published on 10 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-31832 in the wild and no public exploit code.

Affected packages and fixed versions:
- Umbraco.Cms (NuGet): affected from 14.0.0; fixed in 16.5.1
- Umbraco.Cms (NuGet): affected from 14.0.0; fixed in 16.5.1
- Umbraco.Cms (NuGet): affected from 17.0.0; fixed in 17.2.2
- Umbraco.Cms (NuGet): affected from 17.0.0; fixed in 17.2.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31832/ (Markdown: https://insights.sbomify.com/CVE-2026-31832/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31832
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31832
- OSV: https://osv.dev/vulnerability/CVE-2026-31832

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31832/
Summaries are generated and may contain mistakes; the official description above is the record.