CVE-2026-32639Winter: Broken access control in `Cms\Controllers\Index` allows cross-template actions and unauthorized asset uploads

Official description

Winter CMS is a content management system built on the Laravel PHP framework. In versions up to and including 1.2.12, the CMS section's Theme Editor AJAX handlers did not enforce per-template-type permission checks, allowing a backend user with any single CMS permission to act on template types outside their authorized scope. The CMS controller gated access to the section as a whole using OR-logic across its five permissions, but individual handlers such as onSave(), onDelete(), and onDeleteTemplates() did not verify that the user held the specific permission for the requested template type, so a user with only cms.manage_pages could craft AJAX requests to delete layouts, modify partials, or read content files. Separately, the AssetList widget was registered for any user who passed the controller gate regardless of the cms.manage_assets permission, and its onUpload() handler omitted the theme-validation call present on the other mutating handlers, permitting unauthorized file uploads into the active theme's asset directory. Exploitation requires an authenticated backend account holding at least one of the CMS Theme Editor permissions. 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-5c4f-9pq9-6c77 x_refsource_CONFIRM
• https://github.com/wintercms/winter/commit/164c62524e8abc153d09c6c35916278bdb746a2b x_refsource_MISC
• https://github.com/wintercms/winter/commit/5391afa242eba3c476869035b7492e50a262c46b x_refsource_MISC
• https://github.com/wintercms/winter/releases/tag/v1.2.13 x_refsource_MISC