CVE-2026-24907: October CMS has Stored XSS via Event Log Mail Preview
A stored cross-site scripting (XSS) vulnerability was identified in the Event Log mail preview feature. When viewing logged mail messages, HTML content was rendered in an iframe without proper sandboxing, allowing JavaScript execution in the viewer's browser context.
Impact - Stored XSS via mail template content rendered in Event Log - Could allow privilege escalation if a superuser views a malicious log entry - Requires authenticated backend access with mail template editing permissions - Requires a superuser to view the specific Event Log entry to trigger
Patches The vulnerability has been patched in v3.7.14 and v4.1.10. All users are encouraged to upgrade to the latest patched version.
Workarounds If upgrading immediately is not possible: - Restrict mail template editing permissions to fully trusted administrators only - Restrict Event Log viewing permissions to minimize exposure
References - Reported by Chris Alupului
Other sources
October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the Event Log mail preview feature. When viewing logged mail messages, HTML content was rendered in an iframe without proper sandboxing, allowing JavaScript execution in the viewer's browser context. This issue has been fixed in versions 3.7.14 and 4.1.10. If users are unable to update immediately, workarounds include restricting mail template editing permissions to fully trusted administrators only and restricting Event Log viewing permissions to minimize exposure.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-24907?
CVE-2026-24907 is classified as a high-severity stored cross-site scripting (XSS) vulnerability.
How do I fix CVE-2026-24907?
To fix CVE-2026-24907, upgrade October CMS to version 3.7.14 or later, or to version 4.1.10 or later.
What versions of October CMS are affected by CVE-2026-24907?
CVE-2026-24907 affects October CMS versions prior to 3.7.14 and 4.1.10.
What feature in October CMS is vulnerable in CVE-2026-24907?
The Event Log mail preview feature in October CMS is vulnerable to stored XSS in CVE-2026-24907.
What type of vulnerability is CVE-2026-24907?
CVE-2026-24907 is a stored cross-site scripting (XSS) vulnerability.