CVE-2026-24907 October CMS has Stored XSS via Event Log Mail Preview
Attackers can execute arbitrary JavaScript in admin browsers via unsandboxed HTML in the Event Log mail preview, potentially leading to account takeover.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-24907?
CVE-2026-24907 is a medium-severity cross-site scripting vulnerability in Octobercms October, published on 14 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-24907?
4 open source packages ship an affected version, including october/system. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
october/system Packagist | All versions | 3.7.14 |
october/system Packagist | All versions | 3.7.14 |
october/system Packagist | From 4.0.0 | 4.1.10 |
october/system Packagist | From 4.0.0 | 4.1.10 |
Products include Octobercms October.
How do I fix CVE-2026-24907?
Upgrade october/system to a fixed version for your release line: 3.7.14 or 4.1.10.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-24907 being exploited?
There is no known exploitation of CVE-2026-24907 in the wild and no public exploit code.
Other vulnerabilities in Octobercms October
Sources
Also known as GHSA-j4j5-9x6g-rgxc.