CVE-2024-54149 in Winter
Summary
by MITRE • 12/09/2024
Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Winter CMS prior to versions 1.2.7, 1.1.11, and 1.0.476 allow users with access to the CMS templates sections that modify Twig files to bypass the sandbox placed on Twig files and modify resources such as theme customisation values or modify, or remove, templates in the theme even if not provided direct access via the permissions. As all objects passed through to Twig are references to the live objects, it is also possible to also manipulate model data if models are passed directly to Twig, including changing attributes or even removing records entirely. In most cases, this is unwanted behavior and potentially dangerous. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any of the following permissions: `cms.manage_layouts`; `cms.manage_pages`; or `cms.manage_partials`. The Winter CMS maintainers strongly recommend that these permissions only be reserved to trusted administrators and developers in general. The maintainers of Winter CMS have significantly increased the scope of the sandbox, effectively making all models and datasources read-only in Twig, in versions 1.2.7, 1.1.11, and 1.0.476. Thse who cannot upgrade may apply commit fb88e6fabde3b3278ce1844e581c87dcf7daee22 to their Winter CMS installation manually to resolve the issue. In the rare event that a Winter user was relying on being able to write to models/datasources within their Twig templates, they should instead use or create components to make changes to their models.
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Analysis
by VulDB Data Team • 06/24/2025
Winter CMS represents a content management system built upon the Laravel PHP framework that has been found to contain a critical sandbox bypass vulnerability affecting multiple release versions. This vulnerability stems from insufficient restrictions within the Twig templating engine implementation, specifically allowing users with access to CMS templates to circumvent the intended security boundaries. The flaw exists in how the system handles object references passed to Twig templates, where all objects are direct references to live objects rather than isolated copies, creating an avenue for unauthorized manipulation of underlying data structures.
The technical implementation of this vulnerability enables attackers with specific backend permissions to exploit the system's template management capabilities. Users possessing permissions such as cms.manage_layouts, cms.manage_pages, or cms.manage_partials can leverage this flaw to modify theme customization values, alter or delete templates, and manipulate model data directly through Twig files. This represents a significant elevation of privileges since the sandbox mechanism that should prevent such modifications is bypassed, allowing for potentially dangerous operations including attribute changes and record deletions. The vulnerability operates at the intersection of CWE-276, which addresses improper privilege management, and CWE-94, concerning code injection vulnerabilities, as it enables unauthorized code execution within the templating context.
The operational impact of this vulnerability extends beyond simple template manipulation to encompass potential data integrity compromise and unauthorized system modification. Attackers can exploit this weakness to alter the fundamental behavior of the CMS by modifying theme components, potentially leading to complete system compromise if the modified templates interact with sensitive system functions. The risk is particularly elevated because the vulnerability requires only access to the backend with specific template permissions, which may be granted to less trusted users in organizations with shared administrative responsibilities. This aligns with ATT&CK technique T1078.004, which covers valid accounts with elevated privileges, and T1566.001, concerning spearphishing via social media, as attackers could potentially gain access through social engineering to acquire the necessary permissions.
The Winter CMS development team addressed this vulnerability by implementing enhanced sandbox restrictions in versions 1.2.7, 1.1.11, and 1.0.476, making all models and data sources read-only within Twig contexts. This represents a fundamental architectural change that prevents the direct manipulation of live objects through template execution. For organizations unable to upgrade immediately, a manual patch is available through commit fb88e6fabde3b3278ce1844e581c87dcf7daee22, which implements similar restrictions. The recommended mitigation approach emphasizes proper permission management and the use of components for data modification rather than direct template manipulation, aligning with security best practices for content management systems. Organizations should also consider implementing principle of least privilege models and regular security audits to prevent unauthorized access to backend systems with template management capabilities, ensuring that only trusted administrators possess the elevated permissions required to exploit this vulnerability.