CVE-2026-56393: Craftcms/cms Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4mgv-366x-qxvx",
  "modified" : "2026-08-06T21:39:51Z",
  "published" : "2026-03-03T20:58:07Z",
  "aliases" : [ "CVE-2026-56393" ],
  "summary" : "Craft CMS Vulnerable to Stored XSS in Settings Names and Field Options",
  "details" : "## Overview of all XSS Reports\n\nMultiple stored XSS vulnerabilities were found in Craft CMS. They were split into **4 reports** as follows:\n\n| Report | What's Vulnerable | Why Separate |\n|--------|-------------------|--------------|\n| **This Report (1)** | Multiple settings names | Twig Template: `_includes/forms/checkbox.twig` |\n| **Report 2** | Entry Types Name | Twig Template: `_includes/forms/editableTable.twig` |\n| **Report 3** | Card Attributes in Field Layout | `helpers/Cp.php` |\n| **Report 4 (Commerce)** | Product Type Name | Source in Commerce, sink in CMS - will report this one via Commerce GHSA |\n\nReports 2, 3, and 4 are clearly distinct locations. For this report (Report 1), it was not clear whether to split or consolidate these 7 bugs. The bug report was consolidated and the final categorization should be left to the judgement of the user.\n\n**Note:** This overview is only in this Report. Other reports only reference this one.\n\n---\n## Summary\n\nStored XSS in multiple settings. Names/labels are rendered without sanitization via `checkbox.twig` template which uses `{{ label|raw }}`.\n\n---\n## Affected Sources\n\n| #   | Source (injection point)                                                 | Sink (where payload reflects)                 |\n| --- | ------------------------------------------------------------------------ | --------------------------------------------- |\n| 1   | Section Name (`/admin/settings/sections`)                                | Entries field -> Sources checklist            |\n| 2   | Volume Name (`/admin/settings/assets/volumes/{vol_id}`)                  | Assets field -> Sources checklist             |\n| 3   | User Group Name (`/admin/settings/users/groups`)                         | Users field -> Sources, User permissions page |\n| 4   | Global Set Name (`/admin/settings/globals`)                              | User permissions page                         |\n| 5   | Generated Fields Name (Volumes, Users, etc.)                             | Card Attributes checkboxes                    |\n| 6   | Checkboxes & Radio Buttons Field Option Label (`/admin/settings/fields`) | User profile pages                            |\n| 7   | Custom Sources Label (`/admin/users` -> Customize Sources)               | Users field -> Sources checklist              |\n\n---\n## Proof of Concept\n\n### Required Permissions (Attacker)\n- Admin access\n- `allowAdminChanges` is enabled in production, which is against our [security recommendations](https://craftcms.com/knowledge-base/securing-craft).\n\n### Bugs 1-3: Section, Volume, User Group Names\n\n1. Log in as admin.\n2. Inject payload in one of these:\n   - **Settings** -> **Sections** -> Create/edit section -> **Name**\n   - **Settings** -> **Assets** -> **Volumes** -> Create/edit volume -> **Name**\n   - **Settings** -> **Users** -> **User Groups** -> Create/edit group -> **Name**\n3. Set **Name** to:\n```html\n<img src=x onerror=\"alert('XSS')\">\n```\n4. Save.\n5. Go to **Settings** -> **Fields** -> Create new field.\n6. To trigger the XSS payload: Set **Field Type** to \"Entries\" (for Sections), \"Assets\" (for Volumes), or \"Users\" (for User Groups). The alert fires when the Sources checkbox list renders.\n\n**Note:** User Group Name also reflects on **User permissions page** under **User Groups** section (`/admin/users/{id}/permissions`).\n\n---\n\n### Bug 4: Global Set Name\n\n1. Go to **Settings** -> **Globals** (`/admin/settings/globals`).\n2. Create/edit a Global Set, set **Name** to payload.\n3. Save.\n4. Go to **Users** -> Edit any user -> **Permissions** tab (`/admin/users/{id}/permissions`).\n5. Alert fires because our payload got rendered in the \"Global Sets\" permissions section without encoding/sanitization.\n\n---\n\n### Bug 5: Generated Fields Name\n\n1. Go to **Settings** -> **Assets** -> **Volumes** -> Create/Edit a volume.\n2. Scroll to **Generated Fields** section.\n3. Add a field, set **Name** to payload:\n```html\n<img src=x onerror=\"alert('XSS')\">\n```\n4. Save & Notice the alert. The payload renders in the **Card Attributes** checkbox list below it.\n\n---\n\n### Bug 6: Checkboxes/Radio Buttons Option Label\n\n1. Go to **Settings** -> **Fields** (`/admin/settings/fields`).\n2. Create new field, set **Field Type** to \"Checkboxes\" or \"Radio Buttons\".\n3. In **Field Options**, add an option with **Label** set to payload.\n4. Save the field.\n5. Go to **Settings** -> **Users** -> **User Profile Fields** (`/admin/settings/users/fields`).\n6. Add the created field to the layout and save.\n7. Alert fires on any user profile page (`/admin/users/{id}`).\n\n---\n\n### Bug 7: Custom Sources Label\n\n1. Go to **Users** (`/admin/users`).\n2. Click the three dots icon -> **Customize Sources**.\n3. Create a new custom source, set **Label** to payload.\n4. Save.\n5. Go to **Settings** -> **Fields** -> Create new field.\n6. Set **Field Type** to \"Users\".\n7. Alert fires in the Sources checkbox list.\n\n## Resources\n\nhttps://github.com/craftcms/cms/commit/943152d2246b36f12adf161a03b8695b773d9276\nhttps://github.com/craftcms/cms/commit/67780a778c6ec04e68e64a0b1177c168306144a2",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0-RC1"
      }, {
        "fixed" : "5.9.0-beta.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-RC1"
      }, {
        "fixed" : "4.17.0-beta.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-4mgv-366x-qxvx"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-56393"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/67780a778c6ec04e68e64a0b1177c168306144a2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/943152d2246b36f12adf161a03b8695b773d9276"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/craft-cms-multiple-stored-cross-site-scripting-in-settings-names-and-field-options"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-03T20:58:07Z",
    "nvd_published_at" : null
  }
}