XSS in Octobercms October

CVE-2026-27937

October is a Content Management System (CMS) and web platform. Prior to 3.7.16 and 4.1.16, a reflected Cross-Site Scripting (XSS) vulnerability was identified in the backend DataTable widget where a query parameter was rendered without proper output escaping. This vulnerability is fixed in 3.7.16 and 4.1.16.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (12.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-27937: held from 0.001 to 0.002.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-27937?
CVE-2026-27937 is a low-severity vulnerability in Octobercms October, classified under Cross-site Scripting. CVSS score: 3.1/10. Published 2026-04-21.
How severe is CVE-2026-27937?
Low severity. CVSS v3 base score is 3.1 out of 10.