HOMEVULNERABILITIESCVE-2021-29454
HIGH

CVE-2021-29454

CWE-74Published: January 10, 2022· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-29454 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
smarty1 product(s)
smarty
Source: NVD CPE · 6 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71
PATCHhttps://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71
ADVISORYhttps://github.com/smarty-php/smarty/releases/tag/v3.1.42
ADVISORYhttps://github.com/smarty-php/smarty/releases/tag/v4.0.2
ADVISORYhttps://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6m
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/05/msg00005.html
ADVISORYhttps://packagist.org/packages/smarty/smarty
ADVISORYhttps://security.gentoo.org/glsa/202209-09
ADVISORYhttps://www.debian.org/security/2022/dsa-5151
ADVISORYhttps://www.smarty.net/docs/en/language.function.math.tpl
ADVISORYhttps://github.com/smarty-php/smarty/releases/tag/v3.1.42
ADVISORYhttps://github.com/smarty-php/smarty/releases/tag/v4.0.2
ADVISORYhttps://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6m
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/05/msg00005.html
ADVISORYhttps://packagist.org/packages/smarty/smarty
ADVISORYhttps://security.gentoo.org/glsa/202209-09
ADVISORYhttps://www.debian.org/security/2022/dsa-5151
ADVISORYhttps://www.smarty.net/docs/en/language.function.math.tpl

All References (22)

→
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

Quick Facts

CVE IDCVE-2021-29454
CVSS Score8.8 / 10
SeverityHIGH
WeaknessCWE-74
CISA KEVNo
Affected3 vendor(s)
PublishedJan 10, 2022

Related CVEs (CWE-74)

CVE-2022-24760
10.0
CVE-2014-8423
10.0
CVE-2024-42472
10.0
CVE-2020-26282
10.0
CVE-2026-56699
10.0
CVE-2024-38366
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-29454 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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