CVE-2026-25133

Description

A stored cross-site scripting (XSS) vulnerability was identified in the SVG sanitization logic. The regex pattern used to strip `on*` event handler attributes could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries. ### Impact - Stored XSS via malicious SVG files uploaded through the Media Manager - Could allow privilege escalation if a superuser views or embeds the malicious SVG - Requires authenticated backend access with media upload permissions (`media.library.create`) - SVG must be viewed or embedded in a page to trigger ### Patches The vulnerability has been patched in v3.7.14 and v4.1.10. All users are encouraged to upgrade to the latest patched version. ### Workarounds If upgrading immediately is not possible: - Disable SVG uploads by adding `svg` to the blocked extensions in media configuration - Set `media.clean_vectors` to `true` in configuration (enabled by default) ### References - Reported by Pentest-Tools.com

Affected packages (1)

• Packagist/october/rain>= 4.0.0, < 4.1.10

CVSS scores

References (3)

• ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-25133
• PATCHhttps://github.com/octobercms/october
• WEBhttps://github.com/octobercms/october/security/advisories/GHSA-gcqv-f29m-67gr