CVE-2026-111624CWE-306

CVE-2026-111624

Low · published October 16, 2026

CVSS v3.1
3.7
EPSS
0%
Percentile
22.5
In the wild
Unconfirmed
What it is

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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

The record
Technical detail
CVSS v3.1
3.7 · LOW
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
6.3 · 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
EPSS
0.00309 · 22.5th percentile
Weakness
CWE-306 · Missing Authentication for Critical Function
Published
2026-10-16T22:17Z
References (8)
https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHub.cs#L9-L11 · [email protected]https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHubUpdater.cs#L58 · [email protected]https://github.com/umbraco/Umbraco-CMS/commit/243e082479c777d0f585bbd2f8db571607767b22 · [email protected]https://github.com/umbraco/Umbraco-CMS/commit/b4f6cfc9d0955f9d8443e68353db4a692e91bd94 · [email protected]https://github.com/umbraco/Umbraco-CMS/releases/tag/release-17.7.1 · [email protected]https://github.com/umbraco/Umbraco-CMS/releases/tag/release-18.2.1 · [email protected]https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-4c5q-6c64-96j7 · [email protected]https://www.vulncheck.com/advisories/umbraco-cms-before-17.7.1-and-18.2.1-missing-authorization-on-signalr-hubs · [email protected]
EPSS history
Timeline
  • 18 OCT 03:27Z
    EPSS moved — → 0%
    epss
  • 16 OCT 17:39Z
    Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs
    cvelistv5
  • 16 OCT 17:39Z
    Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs
    cvelistv5