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CVE-2026-72778 high CVSS 8.8

Vulnerability in craftcms/cms (CVE-2026-72778)

Summary

Vulnerability in craftcms/cms (CVE-2026-72778). Successful exploitation can lead to full system takeover. Exploitable via condition.config. Mitigation: upgrade to 4.18.2 or later.

Original description

The description as published by the source.

Craft CMS has an authenticated remote code execution issue in the control panel element-search condition handling.

Craft cleans the outer request-controlled condition array with Component::cleanseConfig(), but Conditions::createCondition() later decodes and merges the JSON string in condition.config without re-running cleanseConfig() on the decoded/merged configuration.

Because condition.config is a JSON string during the first cleanse, Yii special config keys such as as ... and on ... can be hidden inside it. After JSON decoding, those keys reach FieldLayout object creation and are interpreted by Yii as behavior/event configuration.

The RCE is semi-blind: the trigger endpoint returns a normal JSON response, and the command output is verified via a server-side file-write side effect retrieved in a subsequent request.

Preconditions

  • The attacker needs an authenticated Craft control panel session.
  • A valid CSRF token is required.

Impact

An authenticated control panel user can inject Yii behavior/event configuration after Craft’s intended config cleanse boundary. In the confirmed local lab, this led to command execution as the PHP/web user.

Potential attacker impact:

  • Execute operating system commands as the PHP/web user.
  • Read Craft secrets, environment variables, and application configuration.
  • Access database credentials and stored site content.
  • Modify site content, users, and application state.
  • Pivot to internal services reachable from th…

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-2026-72778 has been found in craftcms/cms.
Attackers can target a specific entry point like condition.config over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade craftcms/cms to 4.18.2 or later.
If unsure, ask your IT team or search "craftcms/cms CVE-2026-72778" on the vendor's site.

CVE-2026-72778 (craftcms/cms) — CWE-915 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: condition.config
Patched: 4.18.2 — 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-915) exists in craftcms/cms. Attackers reach the vulnerable code path via condition.config.

📍 Affected scope

Check the vendor advisory for the affected versions of craftcms/cms. Attack surface: condition.config.

🔥 Severity

Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 4.18.2.

🛡️ 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 '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

  1. 1
    Identify 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。

  2. 2
    Apply patch patch 
    Upgrade craftcms/cms to 4.18.2

    ステージング環境で 4.18.2 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

composer craftcms/cms
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.18.2"}]}]
Packagist craftcms/cms
[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0-RC1"},{"fixed":"4.18.2"}]}]

References

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