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Medium · 4.8 CVE-2026-25133 EUVD-2026-22705GHSA-gcqv-f29m-67gr

October CMS has Stored XSS via SVG Filter Bypass

Published Apr 14, 2026 · Updated Apr 16, 2026 · Assigned by GitHub_M

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 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.

Affected products

VendorProductAffectedFixed
octobercms october < 3.7.14, >= 4.0.0, < 4.1.10 —

Affected packages

EcosystemPackageAffectedFixedRecord
Packagist october/rain >= 4.0.0, < 4.1.10 4.1.10 GHSA-gcqv-f29m-67gr
Packagist october/rain < 3.7.14 3.7.14 GHSA-gcqv-f29m-67gr

References