CVE-2026-72778: Craft CMS Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-265m-7826-wjqm",
  "modified" : "2026-09-01T21:07:23Z",
  "published" : "2026-08-06T20:45:00Z",
  "aliases" : [ "CVE-2026-72778" ],
  "summary" : "Craft CMS: Authenticated RCE via `condition.config` JSON cleanse bypass",
  "details" : "Craft CMS has an authenticated remote code execution issue in the control panel element-search condition handling.\n\nCraft 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.\n\nBecause `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.\n\nThe 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.\n\n## Preconditions\n\n- The attacker needs an authenticated Craft control panel session.\n- A valid CSRF token is required.\n\n## Impact\n\nAn 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.\n\nPotential attacker impact:\n- Execute operating system commands as the PHP/web user.\n- Read Craft secrets, environment variables, and application configuration.\n- Access database credentials and stored site content.\n- Modify site content, users, and application state.\n- Pivot to internal services reachable from the Craft host or container.\n- Cause denial of service or establish persistence depending on deployment permissions.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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" : "5.0.0-RC1"
      }, {
        "fixed" : "5.10.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-RC1"
      }, {
        "fixed" : "4.18.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-265m-7826-wjqm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-72778"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/353b5d676c88a854c9f6409ad83b837ca0c0e8da"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/789789dc9e2a4e2f2562f51aaf879fb7757d8340"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/releases/tag/4.18.2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/releases/tag/5.10.6"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/craft-cms-rc1-before-authenticated-rce-via-condition-config"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-915" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-06T20:45:00Z",
    "nvd_published_at" : null
  }
}