#VU61664 Code Injection in Smarty - CVE-2021-29454

Vulnerability identifier: #VU61664

Vulnerability 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

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Smarty
Web applications / CMS

Vendor: smarty.php.net

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 - 3.1.41, 4.0.0 - 4.0.1

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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

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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.