CVE-2021-21408

mediumpriority · track · 36EPSS 0.021 · 81 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.08% (81st) EPSS

CVSS 6.5 · medium

Is it mine?

11 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Smarty is a template engine for PHP, facilitating the separation of presentation (HTML/CSS) from application logic. Prior to versions 3.1.43 and 4.0.3, template authors could run restricted static php methods. Users should upgrade to version 3.1.43 or 4.0.3 to receive a patch.

cvss

Technical severity, 0–10. One row per scoring source.

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–8.8

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · security-advisories@github.comexploitability 2.8 · impact 5.9

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USprimaryCWE-20US

affected products (11)

Products and version ranges known to be affected.

smarty-php smarty≤ < 3.1.43enisa_euvdEU
smarty-php smarty4.0.0, → 4.0.3enisa_euvdEU
debian debian linux= 10.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
debian debian linux= 11.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
debian debian linux= 9.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
fedoraproject fedora= 36nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 37nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
smarty smarty< 3.1.43nvdUScpe:2.3:a:smarty:smarty:*:*:*:*:*:*:*:*
smarty smarty4.0.0 → 4.0.3nvdUScpe:2.3:a:smarty:smarty:*:*:*:*:*:*:*:*
Packagist smarty/smarty< 3.1.43osvUSpkg:composer/smarty/smarty
Packagist smarty/smarty4.0.0 → 4.0.3osvUSpkg:composer/smarty/smarty

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-4h9c-v5vg-5m6mAccess to restricted PHP code by dynamic static class access in smarty2022-01-12ghsa · osvUS
### Impact Template authors could run restricted static php methods. ### Patches Please upgrade to 3.1.40 or higher. ### References See the [documentation on Smarty security features](https://www.smarty.net/docs/en/advanced.features.tpl#advanced.features.security) on the static_classes access filter. ### For more information If you have any questions or comments about this advisory please open an issue in [the Smarty repo](https://github.com/smarty-php/smarty)

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2022-01-10modified 2026-06-17

related (25,193)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2026-88771US	critical9.8OT critical	82.2% (100th)	KEV	2026-09-27
Improper input validation vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS,…
CVE-2026-93952US	—OT critical	1.38% (72nd)	KEV	2026-09-22
VeloCloud Orchestrator (VCO) on-prem has a security issue where this issue may allow a remote attacker to access privileged internal functionality and impact the VCO host. Successf…
CVE-2026-12569US	critical9.8OT critical	46.0% (99th)	KEV	2026-06-18
A critical remote code execution (RCE) vulnerability has been reported in PTC Windchill PDMlink and PTC FlexPLM. The vulnerability may be exploited through the deserialization of u…
CVE-2026-34910US	—OT critical	90.0% (100th)	KEV	2026-05-22
A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection.
CVE-2026-6973US	—OT critical	34.5% (98th)	KEV	2026-05-07
An Improper Input Validation in Ivanti EPMM before versions 12.6.1.1, 12.7.0.1, and 12.8.0.1 allows a remotely authenticated user with administrative access to achieve remote code…

+25188 more

references (33)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan