CVE-2023-28447 in Smarty
Summary
by MITRE • 03/29/2023
Smarty is a template engine for PHP. In affected versions smarty did not properly escape javascript code. An attacker could exploit this vulnerability to execute arbitrary JavaScript code in the context of the user's browser session. This may lead to unauthorized access to sensitive user data, manipulation of the web application's behavior, or unauthorized actions performed on behalf of the user. Users are advised to upgrade to either version 3.1.48 or to 4.3.1 to resolve this issue. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 04/27/2025
The vulnerability identified as CVE-2023-28447 affects Smarty, a widely-used PHP template engine that serves as a bridge between application logic and user interface rendering. This template engine is employed across numerous web applications and content management systems, making the security implications particularly significant. The flaw manifests in the engine's handling of JavaScript code within templates, where insufficient output escaping mechanisms fail to properly sanitize user-supplied data before rendering it in browser contexts. This vulnerability directly impacts the principle of least privilege and input validation, creating a pathway for malicious actors to inject harmful scripts into web applications that utilize Smarty for their templating needs.
The technical exploitation of this vulnerability stems from improper escaping of JavaScript code within Smarty templates, which creates a cross-site scripting vulnerability categorized under CWE-79 - Improper Neutralization of Input During Web Page Generation. When user input is not adequately sanitized before being processed by the template engine, attackers can inject malicious JavaScript payloads that execute within the context of legitimate user sessions. This allows for session hijacking, data theft, and manipulation of web application behavior through techniques that align with ATT&CK framework's T1059.007 - Command and Scripting Interpreter: JavaScript. The vulnerability specifically affects versions prior to 3.1.48 and 4.3.1, where the template engine's output filtering mechanisms were insufficient to prevent XSS attacks.
The operational impact of this vulnerability extends beyond simple script execution, creating potential for serious security breaches that could compromise entire user sessions and sensitive data repositories. Attackers could leverage this flaw to steal session cookies, access protected user information, or perform unauthorized actions on behalf of authenticated users. The vulnerability's exploitation risk is heightened by the widespread adoption of Smarty across various web platforms, meaning that a successful attack could potentially affect numerous applications simultaneously. The lack of known workarounds forces organizations to rely entirely on upgrading their Smarty installations to mitigate the threat, as no temporary fixes can adequately address the core escaping mechanism failures. This vulnerability represents a critical security gap that could enable sophisticated attacks including credential theft, data exfiltration, and persistent browser-based attacks that maintain access to compromised systems.
Organizations should prioritize immediate remediation by upgrading to Smarty versions 3.1.48 or 4.3.1, which contain the necessary patches to address the improper escaping mechanisms. Security teams should conduct comprehensive vulnerability assessments to identify all systems utilizing affected Smarty versions and implement monitoring for potential exploitation attempts. The remediation process should include thorough testing of upgraded systems to ensure that the patch does not introduce compatibility issues with existing applications. Additionally, organizations should enhance their input validation processes and implement robust content security policies to provide defense-in-depth against similar vulnerabilities. Regular security audits and dependency management practices should be strengthened to prevent future occurrences of such escaping mechanism failures that could compromise web application security and user data protection.