CVE-2026-62992 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. Prior to 5.8.2 (and 4.5.7 on the 4.x line), Security::_checkDir() does not fully resolve symbolic links before validating that a requested path lies within a configured secure directory. An attacker able to place or reference a symlink within a directory Smarty treats as trusted (e.g., a template or config directory) could use it to point outside the intended secure directory, bypassing the containment check and reading arbitrary files accessible to the PHP process. This issue is fixed in versions 5.8.2 and 4.5.7.
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Analysis
by VulDB Data Team • 08/07/2026
The vulnerability identified in Smarty template engine affects versions prior to 5.8.2 and 4.5.7, specifically within the Security::_checkDir() function that handles directory validation for template operations. This flaw represents a classic path traversal issue where symbolic link resolution is insufficiently handled during security checks. The core technical problem manifests when Smarty processes templates or configuration files from directories that contain symbolic links pointing outside the intended secure boundaries. When an attacker places a malicious symbolic link within a directory that Smarty considers trusted, the incomplete path resolution allows bypassing the intended containment mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable arbitrary file reads by exploiting the insufficient symlink handling in the security validation process. An attacker with write access to a directory that Smarty treats as trusted can create symbolic links that point to sensitive system files or directories outside the expected secure boundaries. This allows execution of unauthorized file operations against resources that should remain protected, particularly when the PHP process has elevated privileges or access to sensitive data. The vulnerability specifically targets the Security::_checkDir() method which is responsible for validating that template and configuration file paths remain within designated safe directories.
This issue maps directly to CWE-22 Path Traversal and CWE-352 Cross-Site Request Forgery, with potential ATT&CK framework mappings to T1059 Command and Scripting Interpreter and T1566 Phishing. The vulnerability represents a privilege escalation vector through improper access control mechanisms, where symbolic link resolution failures create an attack surface that allows bypassing intended security boundaries. The flaw is particularly dangerous in web applications where Smarty processes user-supplied template paths or configuration data, as it can be exploited through various attack vectors including file upload capabilities, template injection, or configuration manipulation.
Mitigation strategies should focus on immediate version upgrades to 5.8.2 or 4.5.7, which contain the necessary fixes for proper symlink resolution in directory validation. Organizations should also implement additional security controls such as restricting write access to template directories, implementing proper input sanitization for file paths, and monitoring for unauthorized symbolic link creation within trusted directories. The fix addresses the root cause by ensuring that all symbolic links are fully resolved before performing directory containment checks, thereby preventing attackers from exploiting the path traversal mechanism through carefully crafted symbolic link references.