Server-side template injection in Smarty

1) Code Injection

EUVDB-ID: #VU61664

Risk: High

CVSSv4.0: 6.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-29454

CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')

Exploit availability: No

Description

The vulnerability allows a remote user to execute arbitrary PHP code on the target system.

The vulnerability exists due to improper input validation. A remote user can inject a malicious math string into he PHP template and execute arbitrary PHP code on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Smarty: 3.1 - 4.0.1

CPE2.3

• cpe:2.3:a:smarty_php_net:smarty:3.1:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.2:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.3:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.4:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.5:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.6:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.7:*:*:*:*:*:*:*
• cpe:2.3:a:smarty_php_net:smarty:3.1.8:*:*:*:*:*:*:*

External links

https://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71
https://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6m
https://packagist.org/packages/smarty/smarty
https://github.com/smarty-php/smarty/releases/tag/v3.1.42
https://www.smarty.net/docs/en/language.function.math.tpl
https://github.com/smarty-php/smarty/releases/tag/v4.0.2

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.