Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Umbraco.CMS versions 10.0.0 to before 10.8.7 and 13.0.0 to before 13.5.2, and UmbracoCMS versions 8.0.0 to before 8.18.15, are affected. The Backoffice shows the logout page with a session timeout message about 30 seconds before the server session actually expires, so users may think they are logged out when they still are not. Upgrade Umbraco.CMS to 10.8.7 or 13.5.2, or UmbracoCMS to 8.18.15.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 4.2 | Medium | 3.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0027, the 18th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 22 Oct 2024, 08:04 UTC Published by the maintainers as a GitHub repository advisory
- 31 Oct 2026, 15:23 UTC First seen by agentprime
- 31 Oct 2026, 15:23 UTC Confirmed by OSV