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

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.

Published: 2026-03-10 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-31832 is rated Low Risk (24.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.18%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-31832

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.06% 0.18% +0.12%
2 2026-05-17 0.04% 0.06% +0.02%
3 2026-03-11 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-31832

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 2.5 [email protected]

Weakness enumeration for CVE-2026-31832

GitHub Security Advisory for CVE-2026-31832

GHSA-fpvf-fvp5-996r · Severity: medium · Ecosystem: nuget — Umbraco Backoffice API Allows Unauthorized Modification of Domain Data

Affected software / configurations for CVE-2026-31832

Vendor Product Version Raw CPE
umbraco umbraco_cms >= 14.0.0, < 16.5.1 cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*
umbraco umbraco_cms >= 17.0.0, < 17.2.2 cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*

References for CVE-2026-31832

cvelogic Threat Intelligence