CVE-2023-49273: Umbraco CMS vulnerable to Privilege Escalation using Spoofing

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-12 · updated 2026-06-17
Weakness: CWE-863

Description

Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.8.1, and 12.3.4, users with low privileges (Editor, etc.) are able to access some unintended endpoints. Versions 8.18.10, 10.8.1, and 12.3.4 contain a patch for this issue.

Affected products

Umbraco-CMS: from 8.0.0 before 8.18.10; from 10.0.0 before 10.8.1; from 12.0.0 before 12.3.4 — fixed in 10.8.1, 12.3.4, 8.18.10

How to fix

Upgrade to a fixed version: Umbraco-CMS 10.8.1, 12.3.4, 8.18.10. Check the vendor advisory for mitigations.

References

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