CVE-2021-21265: October CMS October

High severity, CVSS 7.5. EPSS: 1.7% chance of exploitation in the next 30 days.

October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. In October before version 1.1.2, when running on poorly configured servers (i.e. the server routes any request, regardless of the HOST header to an October CMS instance) the potential exists for Host Header Poisoning attacks to succeed. This has been addressed in version 1.1.2 by adding a feature to allow a set of trusted hosts to be specified in the application. As a workaround one may set the configuration setting cms.linkPolicy to force.

Affected products

Published 2021-03-10. Last modified 2026-06-17.