CVE-2026-35445Winter: Authenticated backend users can bypass Users controller permission checks

Official description

Winter CMS is a content management system built on the Laravel PHP framework. In versions prior to 1.2.13, the backend did not validate the handler name submitted through the form postback _handler POST field, allowing an authenticated backend user to invoke arbitrary controller methods, including protected, private, and action-prefixed ones. While AJAX requests validate that handler names match the on[A-Z][\w+]* pattern, the postback path passed the submitted _handler value straight to the handler dispatcher with no such check, so any controller that exposes a public action or conditionally relaxes its $requiredPermissions check could be reached, bypassing the roles and permissions system. The built-in Users controller was affected because it set $requiredPermissions to null for the myaccount action, letting any authenticated backend user invoke user-management methods such as update_onDelete and update_onManualPasswordReset without holding the backend.manage_users permission. This issue is fixed in version 1.2.13.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/wintercms/winter/security/advisories/GHSA-j5jq-cr68-v2xx x_refsource_CONFIRM
• https://github.com/wintercms/winter/pull/1473 x_refsource_MISC
• https://github.com/wintercms/winter/releases/tag/v1.2.13 x_refsource_MISC