CVE-2021-29454: Debian Linux

High severity, CVSS 8.8. EPSS: 1.9% chance of exploitation in the next 30 days.

Smarty is a template engine for PHP, facilitating the separation of presentation (HTML/CSS) from application logic. Prior to versions 3.1.42 and 4.0.2, template authors could run arbitrary PHP code by crafting a malicious math string. If a math string was passed through as user provided data to the math function, external users could run arbitrary PHP code by crafting a malicious math string. Users should upgrade to version 3.1.42 or 4.0.2 to receive a patch.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 36 only; version 37 only
• Smarty Smarty: before 3.1.42 (fixed in 3.1.42); from 4.0.0, before 4.0.2 (fixed in 4.0.2)

Published 2022-01-10. Last modified 2026-06-17.