CVE-2026-111624

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

6.3 Medium

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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

0.31%Unchanged since Oct 17, 2026

What each source reports

CVE List Score used 6.3

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

Record: CVE-2026-111624
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-306
Updated: 2026-11-02

EUVDEUVD-2026-103046 6.3

Record: EUVD-2026-103046
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-q9r6-5jwm-rmgp 6.3

Umbraco CMS before 17.7.1 and 18.2.1 contains a missing authorization vulnerability that allows...

Record: GHSA-q9r6-5jwm-rmgp
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-306
Updated: 2026-11-02

NVD 6.3

Record: CVE-2026-111624
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-306
Updated: 2026-11-02

OSV 6.3

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

Record: CVE-2026-111624
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-306
Updated: 2026-11-02

Affected products

umbraco umbraco-cms

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-111624 is a medium vulnerability (CVSS 6.3) in Umbraco Umbraco-cms, published October 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 23rd percentile. No source names a fixed version.

References

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