Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-72781 high CVSS 8.8

Vulnerability in craftcms/cms (CVE-2026-72781)

Summary

Vulnerability in craftcms/cms (CVE-2026-72781). Successful exploitation can lead to full system takeover. Exploitable via SecurityPolicyInterface. Mitigation: upgrade to 4.18.3 or later.

Original description

The description as published by the source.

The Twig sandbox mechanism in Craft CMS is configured to allow dangerous functionality from the Yii framework, leading to authenticated RCE in a manner similar to previously disclosed vulnerabilities.

The Twig sandbox in Craft CMS works by implementing Twig's SecurityPolicyInterface. The resulting SecurityPolicy class implements the checkMethodAllowed and checkPropertyAllowed methods of the interface. The implementations compare whether the called method or property is in a configured allowlist or is marked with the AllowedInSandbox attribute.

Additionally, SecurityPolicy allows the allowlisting of whole classes, which is shorthand for allowing all methods and properties of that class to be called. Both the allowlists for tags, filters, variables, methods, properties, and classes, as well as the AllowedInSandbox attribute mechanism, are preconfigured by Craft CMS to allow user-defined templates to use core functionality unimpeded. Additionally, Craft CMS project developers can add more to the allowlists or mark their custom methods and so on as safe with AllowedInSandbox.

The SecurityPolicy class's allowlisting mechanism is potentially dangerous, as it allows all methods and properties on an object of the allowed class. This means that the checked object can be a subclass and be allowed. And it means that the allowed methods and properties can be defined on any class of the class hierarchy of the object, which does not have to be the allowed class itself.…

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-2026-72781 has been found in craftcms/cms.
Attackers can target a specific entry point like SecurityPolicyInterface 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 4.18.3 or later.
If unsure, ask your IT team or search "craftcms/cms CVE-2026-72781" on the vendor's site.

CVE-2026-72781 (craftcms/cms) — CWE-693 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: SecurityPolicyInterface / SecurityPolicy / checkMethodAllowed / checkPropertyAllowed
Patched: 4.18.3 — 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-693) exists in craftcms/cms. Attackers reach the vulnerable code path via SecurityPolicyInterface.

📍 Affected scope

Check the vendor advisory for the affected versions of craftcms/cms. Attack surface: SecurityPolicyInterface / SecurityPolicy / checkMethodAllowed / checkPropertyAllowed.

🔥 Severity

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

🔧 How to fix

Update to 4.18.3.

🛡️ 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 '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 4.18.3

    ステージング環境で 4.18.3 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

composer craftcms/cms
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.18.3"}]}]
Packagist craftcms/cms
[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0-RC1"},{"fixed":"4.18.3"}]}]

References

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