Server-side template injection in Smarty

1) Code Injection

EUVDB-ID: #VU61664

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

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

External links

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