CVE-2021-29454

Name: CVE-2021-29454
Creator: NVD / NIST
Published: 2022-01-10T20:15:08+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.93%

Last modified Jun 17, 2026

CVE-2021-29454 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 1.93% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.93%

77.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Smarty	Smarty	< 3.1.42
Smarty	Smarty	>= 4.0.0, < 4.0.2
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Fedoraproject	Fedora	36
Fedoraproject	Fedora	37

References

https://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71Patch, Third Party Advisory
https://github.com/smarty-php/smarty/releases/tag/v3.1.42Release Notes, Third Party Advisory
https://github.com/smarty-php/smarty/releases/tag/v4.0.2Release Notes, Third Party Advisory
https://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6mThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/05/msg00005.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BRAJVDRGCIY5UZ2PQHKDTT7RMKG6WJQQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L777JIBIWJV34HS7LXPIDWASG7TT4LNI/
https://packagist.org/packages/smarty/smartyProduct, Third Party Advisory
https://security.gentoo.org/glsa/202209-09Third Party Advisory
https://www.debian.org/security/2022/dsa-5151Third Party Advisory
https://www.smarty.net/docs/en/language.function.math.tplVendor Advisory
https://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71Patch, Third Party Advisory
https://github.com/smarty-php/smarty/releases/tag/v3.1.42Release Notes, Third Party Advisory
https://github.com/smarty-php/smarty/releases/tag/v4.0.2Release Notes, Third Party Advisory
https://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6mThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/05/msg00005.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BRAJVDRGCIY5UZ2PQHKDTT7RMKG6WJQQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L777JIBIWJV34HS7LXPIDWASG7TT4LNI/
https://packagist.org/packages/smarty/smartyProduct, Third Party Advisory
https://security.gentoo.org/glsa/202209-09Third Party Advisory
https://www.debian.org/security/2022/dsa-5151Third Party Advisory
https://www.smarty.net/docs/en/language.function.math.tplVendor Advisory

Timeline

Published: Jan 10, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-29454?

How severe is CVE-2021-29454?

CVE-2021-29454 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.93% probability of exploitation in the next 30 days.

How do I fix CVE-2021-29454?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-29454?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST