CVE-2026-111624

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

Published Oct 16, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
Umbraco CMS before 17.7.1 and 18.2.1 contains a missing authorization vulnerability that allows unauthenticated clients to connect to the backoffice PreviewHub and BackofficeHub SignalR hubs. Attackers can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Umbraco CMS before 17.7.1 and 18.2.1 contains a missing authorization vulnerability that allows unauthenticated clients to connect to the backoffice PreviewHub and BackofficeHub SignalR hubs. Attackers can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.
Title Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs
First Time appeared Umbraco
Umbraco umbraco Cms
Weaknesses CWE-306
CPEs cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*
Vendors & Products Umbraco
Umbraco umbraco Cms
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 21, 2026, 8:41 PM
Reserved
Oct 16, 2026, 2:31 PM
Status
Awaiting Analysis
Published
Oct 16, 2026, 6:17 PM
Modified
Oct 21, 2026, 9:17 PM