CVE-2026-111624

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

LOW
3.7
CVSS Score
Published: October 16, 2026 at 05:39 PM UTC
Updated: October 21, 2026 at 09:17 PM UTC
1 product affected across 1 vendorUmbraco-CMS

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Severity
LOW3.7
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

3.7LOWVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-306

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