Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2021-21408

Vulnerability in smarty/smarty (CVE-2021-21408)

Summary

Vulnerability in smarty/smarty (CVE-2021-21408). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 4.0.3 or later.

Original description

The description as published by the source.

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.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-21408 has been found in smarty/smarty.
Successful exploitation can lead to full system takeover.
What to do: upgrade smarty/smarty to 4.0.3 or later.
If unsure, ask your IT team or search "smarty/smarty CVE-2021-21408" on the vendor's site.

CVE-2021-21408 (smarty/smarty) — CWE-20
Attack vector: remote (network-reachable) / no user interaction
Patched: 4.0.3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-20) exists in smarty/smarty.

📍 Affected scope

Check the vendor advisory for the affected versions of smarty/smarty.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 4.0.3.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'smarty/smarty' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'smarty/smarty' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で smarty/smarty を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade smarty/smarty to 4.0.3

    ステージング環境で 4.0.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Packagist smarty/smarty
[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0"},{"fixed":"4.0.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details