CVE-2026-24907

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.

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

• 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

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-24907 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.10, 3.7.14); upgrading removes the vulnerable code path.

Kodem intelligence

The vulnerability has been patched in v3.7.14 and v4.1.10. All users are encouraged to upgrade to the latest patched version.

1. What is CVE-2026-24907? CVE-2026-24907 is a medium-severity cross-site scripting (XSS) vulnerability in october/system (composer), affecting versions >= 4.0.0, <= 4.1.9. It is fixed in 4.1.10, 3.7.14. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2026-24907? CVE-2026-24907 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of october/system are affected by CVE-2026-24907? october/system (composer) versions >= 4.0.0, <= 4.1.9 is affected.
4. Is there a fix for CVE-2026-24907? Yes. CVE-2026-24907 is fixed in 4.1.10, 3.7.14. Upgrade to this version or later.
5. Is CVE-2026-24907 exploitable, and should I be worried? Whether CVE-2026-24907 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-24907 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-24907?
   • Upgrade october/system to 4.1.10 or later
   • Upgrade october/system to 3.7.14 or later