How severe is CVE-2026-31834?

CVE-2026-31834 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-31834 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31834?

CVE-2026-31834 affects Umbraco Umbraco Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-31834?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-31834 have an EU (EUVD) identifier?

Yes. CVE-2026-31834 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10937.

When was CVE-2026-31834 published?

CVE-2026-31834 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-31834

CVE-2026-31834 is a high-severity vulnerability in Umbraco Umbraco Cms with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-269.

Key facts

Severity: High (CVSS 3.x base score 7.2)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10937
Weakness: CWE-269
Affected product: Umbraco Umbraco Cms
Published: 2026-03-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-31834?: 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.
How severe is CVE-2026-31834?: CVE-2026-31834 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-31834 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31834?: CVE-2026-31834 affects Umbraco Umbraco Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-31834?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-31834 have an EU (EUVD) identifier?: Yes. CVE-2026-31834 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10937.
When was CVE-2026-31834 published?: CVE-2026-31834 was published on 2026-03-10 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*

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