{"id":"GHSA-2fph-6v5w-89hh","summary":"Craft CMS is Vulnerable to Authenticated Remote Code Execution via Malicious Attached Behavior","details":"## Summary\n\nA Remote Code Execution (RCE) vulnerability exists in Craft CMS 5.x and 4.x that bypasses the security fixes for GHSA-7jx7-3846-m7w7 and GHSA-255j-qw47-wjh5. This vulnerability can be exploited by any authenticated user with control panel access.\n\nThe existing patches add `cleanseConfig()` to `assembleLayoutFromPost()` and various `FieldsController` actions to strip Yii2 behavior/event injection keys (`as ` and `on ` prefixed keys). However, the `fieldLayouts` parameter in `ElementIndexesController::actionFilterHud()` is passed directly to `FieldLayout::createFromConfig()` without any sanitization, enabling the same behavior injection attack chain.\n\n## Impact\n\n- **Attack Type**: Remote Code Execution (RCE)\n- **Authentication Required**: Authenticated user with control panel access (`accessCp` permission)\n\n## Vulnerability Details\n\n### Root Cause\n\nIn `ElementIndexesController::actionFilterHud()` (line 493-494), the `fieldLayouts` body parameter is passed to `FieldLayout::createFromConfig()` without `cleanseConfig()`:\n\n```php\n// ElementIndexesController.php:485-494\nif ($conditionConfig) {\n    $conditionConfig = Component::cleanseConfig($conditionConfig); // conditionConfig IS cleansed\n    $condition = $conditionsService-\u003ecreateCondition($conditionConfig);\n} else {\n    $condition = $this-\u003eelementType()::createCondition();\n}\n\nif (!empty($fieldLayouts)) {\n    // fieldLayouts is NOT cleansed!\n    $condition-\u003esetFieldLayouts(array_map(\n        fn(array $config) =\u003e FieldLayout::createFromConfig($config),\n        $fieldLayouts\n    ));\n}\n```\n\nNote the inconsistency: `conditionConfig` is sanitized with `cleanseConfig()`, but `fieldLayouts` is not.\n\n### Attack Chain\n\n1. Send a `fieldLayouts` array containing config with `\"as \u003cname\u003e\"` prefixed keys\n2. `FieldLayout::createFromConfig($config)` -\u003e `new self($config)` -\u003e `Model::__construct($config)`\n3. `App::configure($this, $config)` processes each key\n4. `\"as rce\"` key -\u003e `Component::__set(\"as rce\", $value)` -\u003e `Yii::createObject($value)` -\u003e instantiates `AttributeTypecastBehavior` and attaches it to the FieldLayout\n5. `\"on *\"` key -\u003e registers a wildcard event handler\n6. `parent::__construct()` -\u003e `init()` -\u003e `setTabs([])` -\u003e `getAvailableNativeFields()` -\u003e `trigger(EVENT_DEFINE_NATIVE_FIELDS)`\n7. The wildcard handler fires -\u003e `AttributeTypecastBehavior::beforeSave()` -\u003e `typecastAttributes()`\n8. `$this-\u003eowner-\u003etypecastBeforeSave` -\u003e resolved via `Component::__get()` -\u003e returns the command string from the behavior's own property\n9. `call_user_func([ConsoleProcessus::class, 'execute'], $command)` -\u003e `shell_exec($command)`\n\n### Prerequisites\n\n- A user account with control panel access","aliases":["CVE-2026-33157"],"modified":"2026-03-25T21:16:24.491249Z","published":"2026-03-24T16:50:42Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-03-24T16:50:42Z","nvd_published_at":"2026-03-24T18:16:09Z","cwe_ids":["CWE-470"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/craftcms/cms/security/advisories/GHSA-2fph-6v5w-89hh"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33157"},{"type":"WEB","url":"https://github.com/craftcms/cms/commit/97e90b4bdee369c1af3ca77a77531132df240e4e"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-255j-qw47-wjh5"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-7jx7-3846-m7w7"},{"type":"PACKAGE","url":"https://github.com/craftcms/cms"},{"type":"WEB","url":"https://github.com/craftcms/cms/releases/tag/5.9.13"}],"affected":[{"package":{"name":"craftcms/cms","ecosystem":"Packagist","purl":"pkg:composer/craftcms/cms"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.6.0"},{"fixed":"5.9.13"}]}],"versions":["5.6.0","5.6.0.1","5.6.0.2","5.6.1","5.6.10","5.6.10.1","5.6.10.2","5.6.11","5.6.12","5.6.13","5.6.14","5.6.15","5.6.16","5.6.17","5.6.2","5.6.3","5.6.4","5.6.5","5.6.5.1","5.6.6","5.6.7","5.6.8","5.6.9","5.6.9.1","5.7.0","5.7.0-beta.1","5.7.0-beta.2","5.7.1","5.7.1.1","5.7.10","5.7.11","5.7.2","5.7.3","5.7.4","5.7.5","5.7.6","5.7.7","5.7.8","5.7.8.1","5.7.8.2","5.7.9","5.8.0","5.8.1","5.8.10","5.8.11","5.8.12","5.8.13","5.8.13.1","5.8.13.2","5.8.14","5.8.15","5.8.16","5.8.17","5.8.18","5.8.19","5.8.2","5.8.20","5.8.21","5.8.22","5.8.23","5.8.3","5.8.4","5.8.5","5.8.6","5.8.7","5.8.8","5.8.9","5.9.0","5.9.0-beta.1","5.9.0-beta.2","5.9.1","5.9.10","5.9.11","5.9.12","5.9.2","5.9.3","5.9.4","5.9.5","5.9.6","5.9.7","5.9.8","5.9.9"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-2fph-6v5w-89hh/GHSA-2fph-6v5w-89hh.json","last_known_affected_version_range":"\u003c= 5.9.12"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"}]}