CVE-2026-62996 in Smarty
Summary
by MITRE • 08/07/2026
Smarty is a template engine for PHP, facilitating the separation of presentation (HTML/CSS) from application logic. From 5.0.0 until 5.8.4, Smarty's stream: resource-name handling does not adequately restrict which PHP stream wrappers and filter chains can be referenced from a template, allowing a php://filter-wrapped resource name to be used to read the contents of arbitrary local files accessible to the PHP process. An attacker able to author or influence a template's resource reference could exploit this to disclose sensitive file contents outside the intended template/config scope. This issue is fixed in version 5.8.4.
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Analysis
by VulDB Data Team • 08/07/2026
The vulnerability in Smarty template engine versions 5.0.0 through 5.8.4 represents a critical path traversal and information disclosure flaw that stems from inadequate input validation in the stream resource handling mechanism. This weakness specifically affects how the engine processes resource names that utilize PHP's stream wrapper functionality, particularly when combined with filter chains that can manipulate data streams. The vulnerability occurs because Smarty fails to properly sanitize or restrict which stream wrappers and filter chains can be referenced within template files, creating an attack surface where maliciously crafted resource names can bypass normal access controls.
The technical exploitation of this vulnerability relies on the ability to construct a php://filter-wrapped resource name that references local files accessible to the PHP process. When Smarty processes such resource names, it does not adequately validate or restrict the stream wrappers being used, allowing attackers to leverage PHP's built-in stream filters to read arbitrary local files. This mechanism essentially bypasses the intended template scope and file access controls, enabling unauthorized file disclosure from the server's filesystem. The vulnerability is particularly dangerous because it can be exploited through template manipulation, making it possible for attackers who can influence template content or creation to access sensitive information such as configuration files, database credentials, application source code, or other confidential data stored on the server.
From an operational impact perspective, this vulnerability creates a significant risk for applications relying on Smarty template engine versions within the affected range. The attack vector is particularly concerning because it allows for arbitrary file reading from the filesystem where the PHP process has access, potentially exposing sensitive data including but not limited to database connection strings, application secrets, user credentials, and system configuration files. This information disclosure can lead to further exploitation opportunities such as privilege escalation, authentication bypass, or complete system compromise depending on what sensitive files are accessible through the PHP process. The vulnerability affects both authenticated and unauthenticated attackers who can influence template content, making it a widespread concern across various web application scenarios.
Security mitigations for this vulnerability should focus on immediate remediation through upgrading to Smarty version 5.8.4 or later, which contains the necessary fixes to properly validate and restrict stream wrapper usage. Organizations should also implement comprehensive input validation at multiple layers of their application architecture, including template rendering components, to prevent malicious resource names from being processed. Additionally, system administrators should review file permissions and access controls for PHP processes to limit what files can be accessed through the web server context, implementing principle of least privilege approaches. This vulnerability aligns with CWE-22 Path Traversal and CWE-200 Information Disclosure categories, and can be mapped to ATT&CK techniques such as T1566 Credential Access and T1083 File and Directory Discovery, highlighting its potential for both information gathering and privilege escalation activities within compromised environments.