{"id":"CVE-2026-25498","aliases":["CLSA-2026-1784682948","EUVD-2026-6844","GHSA-44px-qjjc-xrhq","GHSA-6j87-m5qx-9fqp","GHSA-7jx7-3846-m7w7"],"status":"published","title":"Craft has a potential authenticated Remote Code Execution via malicious attached Behavior","description":"Craft is a platform for creating digital experiences. In versions 4.0.0-RC1 through 4.16.17 and 5.0.0-RC1 through 5.8.21, a Remote Code Execution (RCE) vulnerability exists in Craft CMS where the assembleLayoutFromPost() function in src/services/Fields.php fails to sanitize user-supplied configuration data before passing it to Craft::createObject(). This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an unpatched variant of the behavior injection vulnerability addressed in CVE-2025-68455, affecting different endpoints through a separate code path. This vulnerability is fixed in 5.8.22.","severity":{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.011,"percentile":0.6609,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-470"],"published":"2026-02-09T19:55:06Z","modified":"2026-10-28T02:31:01Z","fixes":[{"ecosystem":"Packagist","package":"craftcms/cms","fixed_in":["5.8.22","4.16.18"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"craftcms/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0-RC1"},{"last_affected":"5.8.21"},{"fixed":"5.8.22"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"craftcms/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0-RC1"},{"last_affected":"4.16.17"},{"fixed":"4.16.18"}]}]},{"source":"osv","ecosystem":"TuxCare:Packagist","package":"craftcms/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.9.15"},{"fixed":"3.9.15-p7+tuxcare"}]}],"versions":["3.9.15","3.9.15-p1+tuxcare","3.9.15-p2+tuxcare","3.9.15-p3+tuxcare","3.9.15-p4+tuxcare","3.9.15-p5+tuxcare","3.9.15-p6+tuxcare"],"bundled":12},{"source":"osv","ecosystem":"Packagist","package":"craftcms/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0-RC1"},{"fixed":"5.8.22"}]}],"versions":["5.0.0","5.0.0-RC1","5.0.1","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.1.0","5.1.1","5.1.10","5.1.2","5.1.3","5.1.4","5.1.5","5.1.6","5.1.7","5.1.8","5.1.9","5.2.0","5.2.0-beta.1","5.2.0-beta.2","5.2.0-beta.3","5.2.0-beta.4","5.2.0-beta.5","5.2.0-beta.6","5.2.1","5.2.10","5.2.2","5.2.3","5.2.4","5.2.4.1","5.2.5","5.2.6","5.2.7","5.2.8","5.2.9","5.3.0","5.3.0-beta.1","5.3.0-beta.2","5.3.0.1","5.3.0.2","5.3.0.3","5.3.1","5.3.2","5.3.3","5.3.4","5.3.5","5.3.6","5.4.0","5.4.0.1","5.4.1","5.4.10","5.4.10.1","5.4.2","5.4.3","5.4.4","5.4.5","5.4.5.1","5.4.6","5.4.7","5.4.7.1","5.4.8","5.4.9","5.5.0","5.5.0.1","5.5.1","5.5.1.1","5.5.10","5.5.2","5.5.3","5.5.4","5.5.5","5.5.6","5.5.6.1","5.5.7","5.5.8","5.5.9","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","5.8.3","5.8.4","5.8.5","5.8.6","5.8.7","5.8.8","5.8.9"]},{"source":"osv","ecosystem":"Packagist","package":"craftcms/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0-RC1"},{"fixed":"4.16.18"}]}],"versions":["4.0.0","4.0.0-RC1","4.0.0-RC2","4.0.0-RC3","4.0.0.1","4.0.1","4.0.2","4.0.3","4.0.4","4.0.5","4.0.5.1","4.0.5.2","4.0.6","4.1.0","4.1.0.1","4.1.0.2","4.1.1","4.1.2","4.1.3","4.1.4","4.1.4.1","4.10.0","4.10.0-beta.1","4.10.0-beta.2","4.10.1","4.10.2","4.10.3","4.10.4","4.10.5","4.10.6","4.10.7","4.10.8","4.11.0","4.11.0.1","4.11.0.2","4.11.1","4.11.2","4.11.3","4.11.4","4.11.5","4.12.0","4.12.1","4.12.2","4.12.3","4.12.4","4.12.4.1","4.12.5","4.12.6","4.12.6.1","4.12.7","4.12.8","4.12.9","4.13.0","4.13.1","4.13.1.1","4.13.10","4.13.2","4.13.3","4.13.4","4.13.5","4.13.6","4.13.7","4.13.8","4.13.9","4.14.0","4.14.0.1","4.14.0.2","4.14.1","4.14.10","4.14.11","4.14.11.1","4.14.12","4.14.13","4.14.14","4.14.15","4.14.2","4.14.3","4.14.4","4.14.5","4.14.6","4.14.7","4.14.8","4.14.8.1","4.14.9","4.15.0","4.15.0-beta.1","4.15.0-beta.2","4.15.0.1","4.15.0.2","4.15.1","4.15.2","4.15.3","4.15.4","4.15.5","4.15.6","4.15.6.1","4.15.6.2","4.15.7","4.16.0","4.16.1","4.16.10","4.16.11","4.16.12","4.16.13","4.16.14","4.16.15","4.16.16","4.16.17","4.16.2","4.16.3","4.16.4","4.16.5","4.16.6","4.16.6.1","4.16.7","4.16.8","4.16.9","4.16.9.1","4.2.0","4.2.0.1","4.2.0.2","4.2.1","4.2.1.1","4.2.2","4.2.3","4.2.4","4.2.5","4.2.5.1","4.2.5.2","4.2.6","4.2.7","4.2.8","4.3.0","4.3.1","4.3.10","4.3.11","4.3.2","4.3.2.1","4.3.3","4.3.4","4.3.5","4.3.6","4.3.6.1","4.3.7","4.3.7.1","4.3.8","4.3.8.1","4.3.8.2","4.3.9","4.4.0","4.4.0-beta.1","4.4.0-beta.2","4.4.0-beta.3","4.4.0-beta.4","4.4.0-beta.5","4.4.0-beta.6","4.4.0-beta.7","4.4.1","4.4.10","4.4.10.1","4.4.11","4.4.12","4.4.13","4.4.14","4.4.15","4.4.16","4.4.16.1","4.4.17","4.4.2","4.4.3","4.4.4","4.4.5","4.4.6","4.4.6.1","4.4.7","4.4.7.1","4.4.8","4.4.9","4.5.0","4.5.0-beta.1","4.5.0-beta.2","4.5.1","4.5.10","4.5.11","4.5.11.1","4.5.12","4.5.13","4.5.14","4.5.15","4.5.2","4.5.3","4.5.4","4.5.5","4.5.6","4.5.6.1","4.5.7","4.5.8","4.5.9","4.6.0","4.6.0-RC1","4.6.1","4.7.0","4.7.1","4.7.2","4.7.2.1","4.7.3","4.7.4","4.8.0","4.8.1","4.8.10","4.8.11","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7","4.8.8","4.8.9","4.9.0","4.9.1","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7"]}],"products":[{"vendor":"craftcms","product":"cms"},{"vendor":"craftcms","product":"craft_cms"},{"vendor":"statamic","product":"cms"}],"references":[{"url":"https://github.com/craftcms/cms/security/advisories/GHSA-7jx7-3846-m7w7","tags":["x_refsource_CONFIRM","Exploit","Patch","Vendor Advisory","advisory","web"]},{"url":"https://github.com/craftcms/cms/commit/395c64f0b80b507be1c862a2ec942eaacb353748","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/craftcms/cms/releases/tag/5.8.22","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://github.com/craftcms/cms/releases/tag/4.16.18","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25498","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-7jx7-3846-m7w7"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25498.json","tags":["advisory"]},{"url":"https://github.com/craftcms/cms","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-25498","title":"Craft has a potential authenticated Remote Code Execution via malicious attached Behavior","description":"Craft is a platform for creating digital experiences. In versions 4.0.0-RC1 through 4.16.17 and 5.0.0-RC1 through 5.8.21, a Remote Code Execution (RCE) vulnerability exists in Craft CMS where the assembleLayoutFromPost() function in src/services/Fields.php fails to sanitize user-supplied configuration data before passing it to Craft::createObject(). This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an unpatched variant of the behavior injection vulnerability addressed in CVE-2025-68455, affecting different endpoints through a separate code path. This vulnerability is fixed in 5.8.22.","status":"published","published":"2026-02-09T19:55:06.558Z","modified":"2026-02-10T15:59:54.896Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-470"],"updated_at":"2026-11-02T13:41:30.911526Z"}],"euvd":[{"id":"EUVD-2026-6844","description":"Craft is a platform for creating digital experiences. In versions 4.0.0-RC1 through 4.16.17 and 5.0.0-RC1 through 5.8.21, a Remote Code Execution (RCE) vulnerability exists in Craft CMS where the assembleLayoutFromPost() function in src/services/Fields.php fails to sanitize user-supplied configuration data before passing it to Craft::createObject(). This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an unpatched variant of the behavior injection vulnerability addressed in CVE-2025-68455, affecting different endpoints through a separate code path. This vulnerability is fixed in 5.8.22.","status":"published","published":"2026-02-09T19:55:06Z","modified":"2026-02-10T15:59:54Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T19:48:42.087959Z"}],"ghsa":[{"id":"GHSA-7jx7-3846-m7w7","title":"Craft CMS Vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior","description":"## Relationship to Previously Patched Vulnerability\n\nThis vulnerability is **in addition to** the RCE vulnerability patched in [GHSA-255j-qw47-wjh5](https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5). That advisory addressed a similar RCE vulnerability that affected two specific routes:\n\n- `/index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings`\n- `/index.php?p=admin%2Factions%2Ffields%2Frender-card-preview`\n\nThis one addresses some additional endpoints that were not covered in the https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5.\n\nThe patched vulnerability used a malicious `AttributeTypecastBehavior` with a wildcard event listener (`\"on *\": \"self::beforeSave\"`) and `__construct()` syntax to trigger RCE via the `typecastBeforeSave` callback. The fix was implemented in commits:\n- [6e608a1](https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef)\n- [27f5588](https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7)\n- [ec43c49](https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593)\n\nThis vulnerability follows the same attack pattern (behavior injection via `\"as \u003cbehavior\u003e\"` syntax) but affects a **different code path** (`assembleLayoutFromPost()` in `Fields.php`) that was **not patched** in those commits. The attack vector uses `typecastAfterValidate` instead of `typecastBeforeSave` and does not require the wildcard event listener syntax, demonstrating that multiple entry points exist for this type of vulnerability.\n\n---\n\n## Executive Summary\n\nA Remote Code Execution (RCE) vulnerability exists in Craft CMS where the `assembleLayoutFromPost()` function in `src/services/Fields.php` fails to sanitize user-supplied configuration data before passing it to `Craft::createObject()`. This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an **unpatched variant** of the behavior injection vulnerability addressed in GHSA-255j-qw47-wjh5, affecting different endpoints through a separate code path.\n\n---\n\n## Vulnerability Details\n\n### Attack Prerequisites\n\n- **Authentication:** Admin-level access required\n- **Network Access:** Access to admin panel (`/admin`)\n\n---\n\n\n### Location\n\n- **File:** `src/services/Fields.php`\n- **Function:** `assembleLayoutFromPost()` (lines 1125-1143)\n- **Root Cause:** Missing `cleanseConfig()` call on user-supplied `fieldLayout` POST parameter\n\n### Vulnerable Code Path\n\n```php\n// src/services/Fields.php:1125-1133\npublic function assembleLayoutFromPost(?string $namespace = null): FieldLayout\n{\n    $paramPrefix = $namespace ? rtrim($namespace, '.') . '.' : '';\n    $request = Craft::$app-\u003egetRequest();\n    $config = JsonHelper::decode($request-\u003egetBodyParam(\"{$paramPrefix}fieldLayout\"));\n    // ... additional config values added ...\n    $layout = $this-\u003ecreateLayout($config);  // \u003c-- No cleanseConfig() call!\n    // ...\n}\n\n// src/services/Fields.php:1089-1093\npublic function createLayout(array $config): FieldLayout\n{\n    $config['class'] = FieldLayout::class;\n    return Craft::createObject($config);  // \u003c-- Untrusted data passed directly\n}\n```\n---\n\n## Attack Chain\n\nThe exploitation leverages Yii2's object configuration system and behavior attachment mechanism:\n\n1. **Behavior Injection:** Attacker includes `'as rce'` key in the `fieldLayout` JSON POST parameter\n2. **Object Creation:** `Craft::createObject()` processes the config through Yii2's `BaseYii::configure()`\n3. **Behavior Attachment:** Yii2's `Component::__set()` detects the `'as '` prefix and attaches the behavior\n4. **RCE Trigger:** When `validate()` is called on the model, `EVENT_AFTER_VALIDATE` fires\n5. **Command Execution:** `AttributeTypecastBehavior` calls the configured typecast function (`ConsoleProcessus::execute`) with the `uid` attribute value as the command\n\n### RCE Gadget Chain\n\n```\nFieldLayout POST parameter\n    → Craft::createObject()\n    → Yii2 Component::__set() with 'as rce' key\n    → AttributeTypecastBehavior attached\n    → Model::validate() called\n    → EVENT_AFTER_VALIDATE triggered\n    → typecastAfterValidate → typecastAttributes()\n    → call_user_func(['Psy\\Readline\\Hoa\\ConsoleProcessus', 'execute'], $command)\n    → Shell command execution\n```\n\n---\n\n## Affected Controllers\n\nThe `assembleLayoutFromPost()` function is called by multiple admin controllers:\n\n| Controller | Action | Permission Required |\n|------------|--------|---------------------|\n| `TagsController` | `actionSaveTagGroup()` | Admin |\n| `CategoriesController` | `actionSaveGroup()` | Admin |\n| `EntryTypesController` | `actionSave()` | Admin |\n| `GlobalsController` | `actionSaveSet()` | Admin |\n| `VolumesController` | `actionSave()` | Admin |\n| `UsersController` | `actionSaveUserFieldLayout()` | Admin |\n| `AddressesController` | `actionSaveAddressFieldLayout()` | Admin |\n\n---\n## References\n\n- https://github.com/craftcms/cms/commit/395c64f0b80b507be1c862a2ec942eaacb353748\n- [GHSA-255j-qw47-wjh5](https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5) - Previously patched RCE vulnerability via behavior injection (affecting different endpoints)\n- [CVE-2024-4990](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-4990) - Related vulnerability that inspired the behavior injection attack pattern\n- [Yii2 GHSA-gcmh-9pjj-7fp4](https://github.com/yiisoft/yii2/security/advisories/GHSA-gcmh-9pjj-7fp4) - Original Yii framework report (framework team declined to fix at framework level)\n\n---","status":"published","published":"2026-02-09T20:36:43Z","modified":"2026-02-09T22:39:16Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-470"],"updated_at":"2026-11-02T14:39:23.728882Z"}],"nvd":[{"id":"CVE-2026-25498","description":"Craft is a platform for creating digital experiences. In versions 4.0.0-RC1 through 4.16.17 and 5.0.0-RC1 through 5.8.21, a Remote Code Execution (RCE) vulnerability exists in Craft CMS where the assembleLayoutFromPost() function in src/services/Fields.php fails to sanitize user-supplied configuration data before passing it to Craft::createObject(). This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an unpatched variant of the behavior injection vulnerability addressed in CVE-2025-68455, affecting different endpoints through a separate code path. This vulnerability is fixed in 5.8.22.","status":"published","published":"2026-02-09T20:15:58.51Z","modified":"2026-06-17T10:24:44.61Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-470"],"updated_at":"2026-11-02T14:12:05.52517Z"}],"osv":[{"id":"CVE-2026-25498","title":"Craft has a potential authenticated Remote Code Execution via malicious attached Behavior","description":"Craft is a platform for creating digital experiences. In versions 4.0.0-RC1 through 4.16.17 and 5.0.0-RC1 through 5.8.21, a Remote Code Execution (RCE) vulnerability exists in Craft CMS where the assembleLayoutFromPost() function in src/services/Fields.php fails to sanitize user-supplied configuration data before passing it to Craft::createObject(). This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an unpatched variant of the behavior injection vulnerability addressed in CVE-2025-68455, affecting different endpoints through a separate code path. This vulnerability is fixed in 5.8.22.","status":"published","published":"2026-02-09T19:55:06.558Z","modified":"2026-10-28T02:31:01.50436393Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-470"],"updated_at":"2026-11-02T15:44:59.438965Z"},{"id":"GHSA-7jx7-3846-m7w7","title":"Craft CMS Vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior","description":"## Relationship to Previously Patched Vulnerability\n\nThis vulnerability is **in addition to** the RCE vulnerability patched in [GHSA-255j-qw47-wjh5](https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5). That advisory addressed a similar RCE vulnerability that affected two specific routes:\n\n- `/index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings`\n- `/index.php?p=admin%2Factions%2Ffields%2Frender-card-preview`\n\nThis one addresses some additional endpoints that were not covered in the https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5.\n\nThe patched vulnerability used a malicious `AttributeTypecastBehavior` with a wildcard event listener (`\"on *\": \"self::beforeSave\"`) and `__construct()` syntax to trigger RCE via the `typecastBeforeSave` callback. The fix was implemented in commits:\n- [6e608a1](https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef)\n- [27f5588](https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7)\n- [ec43c49](https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593)\n\nThis vulnerability follows the same attack pattern (behavior injection via `\"as \u003cbehavior\u003e\"` syntax) but affects a **different code path** (`assembleLayoutFromPost()` in `Fields.php`) that was **not patched** in those commits. The attack vector uses `typecastAfterValidate` instead of `typecastBeforeSave` and does not require the wildcard event listener syntax, demonstrating that multiple entry points exist for this type of vulnerability.\n\n---\n\n## Executive Summary\n\nA Remote Code Execution (RCE) vulnerability exists in Craft CMS where the `assembleLayoutFromPost()` function in `src/services/Fields.php` fails to sanitize user-supplied configuration data before passing it to `Craft::createObject()`. This allows authenticated administrators to inject malicious Yii2 behavior configurations that execute arbitrary system commands on the server. This vulnerability represents an **unpatched variant** of the behavior injection vulnerability addressed in GHSA-255j-qw47-wjh5, affecting different endpoints through a separate code path.\n\n---\n\n## Vulnerability Details\n\n### Attack Prerequisites\n\n- **Authentication:** Admin-level access required\n- **Network Access:** Access to admin panel (`/admin`)\n\n---\n\n\n### Location\n\n- **File:** `src/services/Fields.php`\n- **Function:** `assembleLayoutFromPost()` (lines 1125-1143)\n- **Root Cause:** Missing `cleanseConfig()` call on user-supplied `fieldLayout` POST parameter\n\n### Vulnerable Code Path\n\n```php\n// src/services/Fields.php:1125-1133\npublic function assembleLayoutFromPost(?string $namespace = null): FieldLayout\n{\n    $paramPrefix = $namespace ? rtrim($namespace, '.') . '.' : '';\n    $request = Craft::$app-\u003egetRequest();\n    $config = JsonHelper::decode($request-\u003egetBodyParam(\"{$paramPrefix}fieldLayout\"));\n    // ... additional config values added ...\n    $layout = $this-\u003ecreateLayout($config);  // \u003c-- No cleanseConfig() call!\n    // ...\n}\n\n// src/services/Fields.php:1089-1093\npublic function createLayout(array $config): FieldLayout\n{\n    $config['class'] = FieldLayout::class;\n    return Craft::createObject($config);  // \u003c-- Untrusted data passed directly\n}\n```\n---\n\n## Attack Chain\n\nThe exploitation leverages Yii2's object configuration system and behavior attachment mechanism:\n\n1. **Behavior Injection:** Attacker includes `'as rce'` key in the `fieldLayout` JSON POST parameter\n2. **Object Creation:** `Craft::createObject()` processes the config through Yii2's `BaseYii::configure()`\n3. **Behavior Attachment:** Yii2's `Component::__set()` detects the `'as '` prefix and attaches the behavior\n4. **RCE Trigger:** When `validate()` is called on the model, `EVENT_AFTER_VALIDATE` fires\n5. **Command Execution:** `AttributeTypecastBehavior` calls the configured typecast function (`ConsoleProcessus::execute`) with the `uid` attribute value as the command\n\n### RCE Gadget Chain\n\n```\nFieldLayout POST parameter\n    → Craft::createObject()\n    → Yii2 Component::__set() with 'as rce' key\n    → AttributeTypecastBehavior attached\n    → Model::validate() called\n    → EVENT_AFTER_VALIDATE triggered\n    → typecastAfterValidate → typecastAttributes()\n    → call_user_func(['Psy\\Readline\\Hoa\\ConsoleProcessus', 'execute'], $command)\n    → Shell command execution\n```\n\n---\n\n## Affected Controllers\n\nThe `assembleLayoutFromPost()` function is called by multiple admin controllers:\n\n| Controller | Action | Permission Required |\n|------------|--------|---------------------|\n| `TagsController` | `actionSaveTagGroup()` | Admin |\n| `CategoriesController` | `actionSaveGroup()` | Admin |\n| `EntryTypesController` | `actionSave()` | Admin |\n| `GlobalsController` | `actionSaveSet()` | Admin |\n| `VolumesController` | `actionSave()` | Admin |\n| `UsersController` | `actionSaveUserFieldLayout()` | Admin |\n| `AddressesController` | `actionSaveAddressFieldLayout()` | Admin |\n\n---\n## References\n\n- https://github.com/craftcms/cms/commit/395c64f0b80b507be1c862a2ec942eaacb353748\n- [GHSA-255j-qw47-wjh5](https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5) - Previously patched RCE vulnerability via behavior injection (affecting different endpoints)\n- [CVE-2024-4990](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-4990) - Related vulnerability that inspired the behavior injection attack pattern\n- [Yii2 GHSA-gcmh-9pjj-7fp4](https://github.com/yiisoft/yii2/security/advisories/GHSA-gcmh-9pjj-7fp4) - Original Yii framework report (framework team declined to fix at framework level)\n\n---","status":"published","published":"2026-02-09T20:36:43Z","modified":"2026-04-02T13:29:24.688478228Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-470"],"updated_at":"2026-11-02T15:46:41.002603Z"},{"id":"CLSA-2026-1784682948","title":"TuxCare security update for craftcms/cms (14 CVEs)","description":"TuxCare rebuilt craftcms/cms to address 14 CVEs. Fixed in 3.9.15-p7+tuxcare.","status":"published","published":"2026-08-04T14:52:46Z","modified":"2026-10-15T09:47:59.497016132Z","updated_at":"2026-11-02T15:43:46.482572Z"}]}}