---
id: CVE-2026-35445
title: Winter CMS is a content management system built on the Laravel PHP framework
summary: >-
  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 b…
severity: high
cwe:
  - CWE-285
  - CWE-639
vendor: winter
product: winter/wn-backend-module
affected:
  - winter/wn-backend-module <= 1.2.12
patched:
  - winter/wn-backend-module 1.2.13
published: '2026-08-26'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-35445'
references:
  - url: 'https://github.com/wintercms/winter/pull/1473'
    label: security-advisories@github.com
  - url: 'https://github.com/wintercms/winter/releases/tag/v1.2.13'
    label: security-advisories@github.com
  - url: >-
      https://github.com/wintercms/winter/security/advisories/GHSA-j5jq-cr68-v2xx
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-j5jq-cr68-v2xx'
tags:
  - nvd
  - ghsa
  - composer
epss: 0.00439
epssPercentile: 0.35447
aliases:
  - GHSA-j5jq-cr68-v2xx
ecosystem: composer
ingestedAt: '2026-08-12T15:53:06.196Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-35445)

Affected packages:

- `winter/wn-backend-module <= 1.2.12`

Patched in:

- `winter/wn-backend-module 1.2.13`

Source: https://github.com/advisories/GHSA-j5jq-cr68-v2xx