Is CVE-2026-31834 in the CISA KEV catalog?

No. CVE-2026-31834 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-31834?

CVE-2026-31834 has a CVSS v3 base score of 7.2 (HIGH).

What is the EPSS score for CVE-2026-31834?

CVE-2026-31834 has an EPSS score of 0.26% (17th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-31834

HIGH

7.2

CVSS v3

NVD

Description

Umbraco is an ASP.NET CMS. From 15.3.1 to before 16.5.1 and 17.2.2, 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. This vulnerability is fixed in 16.5.1 and 17.2.2.

CWE-269Improper Privilege Management CWE-284Improper Access Control CWE-862Missing Authorization

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.26%probability of exploitation in 30 days

17thpercentile

Low risk: more likely to be exploited than 17% of all known CVEs.

References

https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vp

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-18.