Code Injection in craftcms/cms (CVE-2026-56382)
Summary
Code injection in craftcms/cms (CVE-2026-56382). Successful exploitation can lead to full system takeover. Exploitable via POST /admin/actions/fields/render-card-preview. Mitigation: upgrade to 5.9.14 or later.
Original description
The description as published by the source.
Craft CMS (composer package craftcms/cms) versions >= 5.5.0 and <= 5.9.13 contain a remote code execution vulnerability in the FieldsController::actionRenderCardPreview() method, which passes the fieldLayoutConfig POST parameter directly to Fields::createLayout() without calling Component::cleanseConfig(). An authenticated admin user can inject Yii2 event handlers (e.g., 'on init' keys) via the fieldLayoutConfig parameter to execute arbitrary PHP code and disclose sensitive information (such as environment variables containing database credentials and CRAFT_SECURITY_KEY). The issue is fixed in version 5.9.14.
Source: NIST National Vulnerability Database NVD GitHub Advisory
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-2026-56382 has been found in craftcms/cms.
Attackers can target a specific entry point like POST /admin/actions/fields/render-card-preview over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 7.2/10.
What to do: upgrade craftcms/cms to 5.9.14 or later.
If unsure, ask your IT team or search "craftcms/cms CVE-2026-56382" on the vendor's site.
CVE-2026-56382 (craftcms/cms) — CWE-94 / CVSS v3 7.2
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /admin/actions/fields/render-card-preview / FieldsController / fieldLayoutConfig / _fldComponent
Patched: 5.9.14 — 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.
Arbitrary code execution (CWE-94) exists in craftcms/cms. Attackers reach the vulnerable code path via POST /admin/actions/fields/render-card-preview.
Check the vendor advisory for the affected versions of craftcms/cms. Attack surface: POST /admin/actions/fields/render-card-preview / FieldsController / fieldLayoutConfig / _fldComponent.
Severity: High (CVSS 7.2/10). Successful exploitation can lead to full system takeover.
Update to 5.9.14.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /admin/actions/fields/render-card-preview requests with malformed payloads or SQL meta-characters. Run grep -r 'craftcms/cms' . 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
-
1Identify exposure identify
grep -r 'craftcms/cms' . | 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
craftcms/cmsを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /admin/actions/fields/render-card-preview' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /admin/actions/fields/render-card-previewへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade craftcms/cms to 5.9.14ステージング環境で 5.9.14 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /admin/actions/fields/render-card-preview on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory vulncheck.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com