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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| umbraco | Umbraco-CMS | 17.0.0 – < 17.7.1, 18.0.0 – < 18.2.1 | 17.7.1 |
References
- GitHub Security Advisory (GHSA-4c5q-6c64-96j7) vendor-advisory
- https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHub.cs#L9-L11 technical-description
- https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHubUpdater.cs#L58 technical-description
- https://github.com/umbraco/Umbraco-CMS/commit/b4f6cfc9d0955f9d8443e68353db4a692e91bd94 patch
- https://github.com/umbraco/Umbraco-CMS/commit/243e082479c777d0f585bbd2f8db571607767b22 patch
- Umbraco-CMS release-18.2.1 Release Notes release-notes
- Umbraco-CMS release-17.7.1 Release Notes release-notes
- VulnCheck Advisory: Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs third-party-advisory