CVE-2026-31832
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedUmbraco 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA broken object-level authorization (BOLA) vulnerability in Umbraco's backoffice API allows authenticated users to assign domain-related data to content nodes without proper authorization checks. The affected API endpoint fails to enforce user permissions based on group privileges or start node restrictions, enabling unauthorized access to content nodes the user should not be able to modify.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 14.0.0, < 16.5.1>= 17.0.0, < 17.2.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Check installed Umbraco versionLocate the Umbraco version by checking the assembly information in the deployed binaries, the admin dashboard under Settings > About, or the umbraco-config.json file if present. Compare the version number to the affected ranges: < 16.5.1 or >= 17.0.0 but < 17.2.2.Affected if The installed version falls within >= 14.0.0 and < 16.5.1, or >= 17.0.0 and < 17.2.2.
-
Verify backoffice API accessibilityConfirm that the Umbraco backoffice API is exposed and accessible to authenticated users. This is typically enabled by default in Umbraco installations. Check network exposure and authentication configuration.Affected if The backoffice API endpoint is reachable without additional network restrictions.
-
Confirm Domains feature is enabledCheck if the Domains feature is enabled in Umbraco by navigating to the content section and examining whether domain assignments can be managed for content nodes. In Umbraco, this feature allows assigning hostnames (domain names) to content nodes.Affected if The Domains feature is available and users can access the domain assignment interface in the backoffice.
-
Review user group permission configurationsExamine the user group permissions in Umbraco under the Users > User Groups section. Check whether users are assigned to groups that have access to content nodes they should not be able to modify, particularly focusing on group privileges related to content editing and domain management.Affected if Users belong to groups with permissions that should restrict their access to certain content nodes but the system may not be enforcing those restrictions.
You are affected if your Umbraco version is within the vulnerable ranges AND the backoffice API with the Domains feature is accessible to authenticated users who may have unintended access to content node domain assignments.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped16.5.117.2.2
Upgrade Umbraco to version 16.5.1 or 17.2.2 (or later) to patch the authorization bypass vulnerability. Additionally, audit user group permissions and start node configurations to ensure proper access controls are in place.
Upgrade to Umbraco CMS 16.5.1 (for v14.x/15.x) or 17.2.2 (for v17.x)
- Identify the current Umbraco CMS version by checking the installed package or project files
- Back up the entire Umbraco installation including database and files before proceeding
- For Umbraco versions >= 14.0.0 and < 16.5.1: Upgrade to version 16.5.1
- For Umbraco versions >= 17.0.0 and < 17.2.2: Upgrade to version 17.2.2
- Verify the upgrade was successful by checking the Umbraco version in the backoffice or about page
- Test that the backoffice functionality works correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-31832 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-31832 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data