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Fencer Vulns
high 8.8

CVE-2021-21408 json

Access to restricted PHP code by dynamic static class access in smarty

published 2022-01-10 4 y ago modified 2026-07-08 4 mo ago also GHSA-4h9c-v5vg-5m6m , EUVD-2022-0443

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist smarty/smarty 3.1.43, 4.0.3
  • smarty smarty 3.1.43, 4.0.3
  • smarty3 Debian 14, Debian 13, Debian 12 3.1.45-1
  • smarty4 Debian 14, Debian 13, Debian 12 4.1.1-1

debian advisories DEBIAN-CVE-2021-21408

  • smarty3 Ubuntu 18.04 LTS 3.1.31+20161214.1.c7d42e4+selfpack1-3ubuntu0.1
  • smarty3 Ubuntu 22.04 LTS 3.1.39-2ubuntu1
  • smarty3 Ubuntu Pro 16.04 LTS 3.1.21-1ubuntu1+esm1
  • smarty3 Ubuntu Pro 20.04 LTS 3.1.34+20190228.1.c9f0de05+selfpack1-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-21408

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-21408 updated cvss 8.8

php-Smarty: template authors could run restricted static php methods

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
18 mo ago

Exploit prediction

2.14% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist smarty/smarty
<3.1.43
>=4.0.0, <4.0.3
3.1.43
4.0.3

Affected products

  • smarty-php smarty

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.