CVE-2026-111624Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs
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No exploitation reported and no EPSS estimate yet.
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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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.
- CVSS
- 3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- Weakness (CWE)
- CWE-306
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 16, 2026
Affected products
umbraco Umbraco-CMS umbraco:cms (from the name) | from 17.0.0 before 17.7.1; from 18.0.0 before 18.2.1 | CNA record |
References
- https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-4c5q-6c64-96j7vendor-advisory
- https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHub.cs#L9-L11technical-description
- https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHubUpdater.cs#L58technical-description
- https://github.com/umbraco/Umbraco-CMS/commit/b4f6cfc9d0955f9d8443e68353db4a692e91bd94patch
- https://github.com/umbraco/Umbraco-CMS/commit/243e082479c777d0f585bbd2f8db571607767b22patch
- https://github.com/umbraco/Umbraco-CMS/releases/tag/release-18.2.1release-notes
- https://github.com/umbraco/Umbraco-CMS/releases/tag/release-17.7.1release-notes
- https://www.vulncheck.com/advisories/umbraco-cms-before-17.7.1-and-18.2.1-missing-authorization-on-signalr-hubsthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.