CVE-2026-79774 in Winter
Summary
by MITRE • 08/25/2026
Winter CMS versions before 1.2.13 contain an incomplete fix for a Twig sandbox escape vulnerability in System\\Twig\\SecurityPolicy that allows authenticated backend users with template-editing permissions to bypass sandbox restrictions. Attackers can exploit method forwarding through Eloquent models and query builders using methods like saveQuietly(), deleteQuietly(), increment(), decrement(), and newQuery() to read and modify arbitrary database records, execute arbitrary SQL, and achieve remote code execution by injecting PHP into template code sections.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/25/2026
Winter CMS versions prior to 1.2.13 suffer from a critical security flaw involving an incomplete remediation of a Twig sandbox escape vulnerability within the System\\Twig\\SecurityPolicy component. This issue specifically impacts authenticated backend users who possess permissions to edit templates, allowing them to bypass intended sandbox restrictions that are designed to limit code execution capabilities. The root cause lies in the framework's handling of Eloquent models and query builders, where method forwarding mechanisms were not adequately restricted by the security policy updates implemented in previous patches. This oversight creates a pathway for attackers to leverage specific model methods such as saveQuietly(), deleteQuietly(), increment(), decrement(), and newQuery() to interact directly with the underlying database layer without proper validation or sandboxing constraints.
The operational impact of this vulnerability is severe, enabling authenticated users to perform actions that should be prohibited within a restricted template environment. By exploiting these forwarded methods, an attacker can read arbitrary records from the database, modify data integrity by altering existing entries, and execute arbitrary SQL queries against the backend system. This level of access effectively neutralizes the security boundaries intended for template editors, transforming what appears to be a limited editing capability into a powerful tool for data exfiltration and manipulation. The ability to inject PHP code directly into template sections further escalates the risk, as it allows for remote code execution on the server hosting the Winter CMS instance. This progression from sandbox bypass to arbitrary SQL execution and finally to remote code execution represents a classic attack chain that compromises the confidentiality, integrity, and availability of the application and its underlying infrastructure.
From a classification perspective, this vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) due to the ability to inject PHP into templates, as well as CWE-798 Use of Hard-coded Credentials if authentication bypass is involved in related contexts, though primarily it reflects CWE-200 Exposure of Sensitive Information through Query Builder misuse and CWE-611 Improper Restriction of XML External Entity Reference or similar input validation failures depending on the specific vector. In terms of MITRE ATT&CK mapping, this exploit corresponds to T1505 Server Software Component: Web Shell as attackers can achieve persistent access via template injection, and T1213 Data from Information Repositories for database exfiltration through arbitrary SQL execution. The vulnerability also touches upon T1059 Command and Scripting Interpreter by allowing the execution of PHP code within the context of the web server process.
To mitigate this risk, organizations running Winter CMS must immediately upgrade to version 1.2.13 or later where these method forwarding restrictions have been properly enforced in the SecurityPolicy class. Administrators should also review user permissions and ensure that template-editing rights are granted only to trusted individuals with a need for such access. Implementing strict input validation and output encoding practices within custom templates can provide an additional layer of defense, although upgrading remains the primary remediation step. Regular security audits and penetration testing focused on CMS-specific vulnerabilities are recommended to identify any residual risks or misconfigurations that could be exploited by attackers seeking to leverage similar weaknesses in other components of the application stack.