#VU61665 Code Injection in Smarty - CVE-2021-21408

Vulnerability identifier: #VU61665

Vulnerability risk: Medium

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21408

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 code on the target system.

The vulnerability exists due to improper input validation. A remote user with access to template can run restricted static PHP methods.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Smarty: 3.1 - 3.1.42, 4.0.0 - 4.0.2

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External links
https://github.com/smarty-php/smarty/commit/19ae410bf56007a5ef24441cdc6414619cfaf664
https://github.com/smarty-php/smarty/releases/tag/v3.1.43
https://github.com/smarty-php/smarty/security/advisories/GHSA-4h9c-v5vg-5m6m
https://github.com/smarty-php/smarty/releases/tag/v4.0.3

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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