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How the CVE works:
A reflected Cross-Site Scripting (XSS) vulnerability exists in the backend DataTable widget of October CMS. The widget renders a query parameter from the backend URL without proper output escaping. An attacker can craft a malicious URL containing JavaScript code in the vulnerable parameter. When a victim with backend access clicks the link, the unescaped parameter is reflected back into the page. The victim’s browser executes the attacker’s script in the context of the October CMS backend. This can lead to session hijacking, data theft, or unauthorized actions. The attack requires user interaction and knowledge of the custom backend URL prefix. The vulnerability affects versions prior to 3.7.16 and 4.1.16. The fix escapes the parameter before rendering, neutralizing injected scripts. Security updates were released on April 21, 2026. Users are advised to upgrade immediately. No public exploit is available at this time. The issue was discovered and reported through GitHub’s advisory system. The vulnerability is classified as low severity due to the required user interaction. However, the impact within the backend can be severe. Proper input sanitization and output encoding are essential to prevent XSS. This case highlights the risk of trusting user-supplied input in URL parameters.
dailycve form:
Platform: October CMS
Version: Affected: 3.7.16, 4.0.0-4.1.16
Vulnerability: Reflected XSS
Severity: Low
date: 2026-04-21
Prediction: 2026-04-21 (same day)
Analytics under heading What Undercode Say:
Check installed October CMS version
php artisan october:version
Search for vulnerable DataTable widget usage
grep -r "DataTable" ./modules/backend/widgets/
Test for reflected XSS (requires backend access)
curl -k "https://your-october-site.com/backend/path?param=<script>alert('XSS')</script>"
Verify patch level
composer show october/october | grep versions
how Exploit:
- Identify a backend URL that uses the DataTable widget (e.g.,
/backend/cms/dashboard). - Inject a malicious script into a query parameter rendered by the widget:
?payload=<script>alert('XSS')</script>.
3. Encode the payload for URL safety: `%3Cscript%3Ealert(%27XSS%27)%3C/script%3E`.
- Deliver the crafted link to a logged‑in backend user via email or message.
- When clicked, the script executes in the victim’s browser, potentially stealing session cookies or performing actions as the victim.
Protection from this CVE
- Upgrade to October CMS v3.7.16 or v4.1.16 immediately.
- If upgrading is not possible, avoid clicking untrusted links while logged into the backend.
- Implement a Content Security Policy (CSP) to restrict script execution.
- Use a web application firewall (WAF) to filter malicious query strings.
- Regularly audit and sanitize all user‑supplied input in custom widgets.
Impact
- An attacker can execute arbitrary JavaScript in the victim’s backend session.
- Potential theft of session cookies, leading to account takeover.
- Unauthorized data access, modification, or deletion within the CMS.
- Defacement of backend interface or redirection to malicious sites.
- Low severity due to required user interaction, but high impact if exploited successfully.
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Sources:
Reported By: github.com
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