CVE-2026-25133 PUBLISHED

October CMS has Stored XSS via SVG Filter Bypass

Assigner: GitHub_M
Reserved: 29.01.2026 Published: 14.04.2026 Updated: 14.04.2026

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 SVG sanitization logic. The regex pattern used to strip event handler attributes (such as onclick or onload) could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries, allowing malicious SVG files to be uploaded through the Media Manager with embedded JavaScript. Exploitation could lead to privilege escalation if a superuser views or embeds the malicious SVG, and requires authenticated backend access with media upload permissions. The SVG must be viewed or embedded in a page for the payload to trigger. This issue has been fixed in versions 3.7.14 and 4.1.10.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 4.8

Product Status

Vendor octobercms
Product october
Versions
  • Version < 3.7.14 is affected
  • Version >= 4.0.0, < 4.1.10 is affected

References

Problem Types

  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE