# Winter CMS CSRF through backend page action routing

Source: https://junglewise.ai/threats/winter-cms-csrf-through-backend-page-action-routing-63f3a65d  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-20. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

Severity: medium · CVSS 6.1 · Published 2026-08-20

Winter CMS is a web content management system used to build and manage websites. Due to improper CSRF protection and request routing, an attacker can trick a logged-in administrator into visiting a malicious link that performs damaging actions without authorization, such as truncating logs, deleting templates, or resetting settings. This requires the victim to have developer-level permissions and to click a link, but no technical sophistication on the victim's part is needed.

Technologies: [winter/wn-backend-module (Packagist)](https://junglewise.ai/threats/technologies/winter-wn-backend-module), [Winter CMS WN Backend Module](https://junglewise.ai/threats/technologies/wn-backend-module). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist), [Winter CMS](https://junglewise.ai/threats/vendors/winter-cms).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Medium severity, with a CVSS score of 6.1, published 20 August 2026.

**Which products and versions are affected?** winter/wn-backend-module (Packagist) >= 1.0.319, < 1.2.14; Winter CMS WN Backend Module >= 1.0.319, < 1.2.14.

**Is there a fix for This vulnerability?** A patch was published on 2026-08-20: Fixed in v1.2.14 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a web application.

**Am I affected?** Check whether you run winter/wn-backend-module (Packagist) or Winter CMS WN Backend Module at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Winter CMS's backend routing failed to restrict AJAX handler-shaped method names from being invoked via GET requests. The vulnerability exists in the `Backend\Classes\Controller::actionExists()` method, which accepted any public controller method as a page action without validating the naming convention. Backend routes are processed through `Route::any()` and CSRF token validation is skipped for HEAD, GET, and OPTIONS requests. Attackers exploited this by crafting URLs like `/backend/system/eventlogs/index_onEmptyLog` that invoke handlers through top-level navigation. The default `SameSite=Lax` session cookie is automatically included on cross-site top-level navigation, allowing a simple link on an attacker-controlled page to execute state-changing operations (log deletion, template deletion, user state alteration, settings reset) without requiring a form submission or JavaScript. The fix restricts page-action dispatch to lowercase method names, reserving all handler-shaped names from URL reachability while preserving normal AJAX handler POST dispatch via the `X-WINTER-REQUEST-HANDLER` header. The patch was released in v1.2.14.

## Affected products

- Winter CMS wn-backend-module >= 1.0.319, < 1.2.14

## Timeline

- 2026-08-20: disclosed: Published to GitHub Advisory Database
- 2026-08-20: patched: Fixed in v1.2.14

## References

- [https://api.github.com/users/NRAwwad](https://api.github.com/users/NRAwwad)
- [https://github.com/NRAwwad](https://github.com/NRAwwad)
- [https://api.github.com/users/NRAwwad/gists%7B/gist_id%7D](https://api.github.com/users/NRAwwad/gists%7B/gist_id%7D)
- [https://api.github.com/users/NRAwwad/repos](https://api.github.com/users/NRAwwad/repos)
- [https://avatars.githubusercontent.com/u/39842950?v=4](https://avatars.githubusercontent.com/u/39842950?v=4)
- [https://api.github.com/users/NRAwwad/events%7B/privacy%7D](https://api.github.com/users/NRAwwad/events%7B/privacy%7D)

## Related threats

- [Winter CMS local file inclusion via LESS @import directives](https://junglewise.ai/threats/cve-2026-63179-winter-cms-local-file-inclusion-via-less-import-directives)
- [Winter CMS FileUpload widget IDOR in attachment metadata](https://junglewise.ai/threats/cve-2026-54256-winter-cms-fileupload-widget-idor-in-attachment-metadata)
- [Winter CMS SQL injection in Backend Filter Widget numberrange scope](https://junglewise.ai/threats/cve-2026-32593-winter-cms-sql-injection-in-backend-filter-widget-numberrange)
- [Winter CMS authorization bypass in Users controller](https://junglewise.ai/threats/cve-2026-35445-winter-cms-authorization-bypass-in-users-controller)
- [Winter CMS stored XSS in Editor Settings custom styles](https://junglewise.ai/threats/cve-2026-32258-winter-cms-stored-xss-in-editor-settings-custom-styles)