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High

Craft CMS: RCE via missing cleanseConfig in FieldsController::actionRenderCardPreview

  • Disclosed: 09.07.2026
  • Updated: 11.10.2026 10:22

The actionRenderCardPreview() method in FieldsController passes the fieldLayoutConfig POST parameter directly to Fields::createLayout() without calling Component::cleanseConfig(). This allows Yii2 event handler injection via on eventName keys in the config array, leading to arbitrary code execution.

This is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, _fldComponent method correctly uses cleanseConfig), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController).

PoC

As an admin user with a valid session:

POST /admin/actions/fields/render-card-preview HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Cookie: CraftSessionId=<session>

fieldLayoutConfig[on+init]=phpinfo&CRAFT_CSRF_TOKEN=<token>

When the FieldLayout object is constructed, Yii2 processes the on init key as an event handler registration. During Component::init(), the init event is triggered, calling phpinfo(). The phpinfo output (which includes environment variables, potentially containing database credentials and CRAFT_SECURITY_KEY) will appear in the response.

Impact

An authenticated admin can achieve RCE through Yii2 event handler injection. While this requires admin access (same as GHSA-4484-8v2f-5748, which was rated moderate), it allows arbitrary PHP function execution and information disclosure via phpinfo.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package craftcms/cms >= 5.5.0, < 5.9.14 5.9.14

References

CVSS score -
CVSS 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
Weakness (CWE)
CWE-94
Platform
Composer
Package
craftcms/cms
Disclosed
09.07.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-86vw-x4ww-x467 - CC BY 4.0

Vulnerability history: craftcms/cms

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (127) in the archive
Total entries
127
First → latest
07.2021 08.2026
Without a fix
6
Exploited in attacks
4

Severity breakdown

  • Critical 9
  • High 41
  • Medium 65
  • Low 12

Disclosures per year

Severity:
  1. Craft CMS: Passkey login accepts replayed WebAuthn assertions
    Critical CVE-2026-72780 >= 5.0.0-RC1, < 5.10.5 5.10.5
  2. Craft CMS: Arbitrary user password reset leading to administrator account takeover
    High CVE-2026-72786 >= 5.0.0-RC1, < 5.10.8 5.10.8
  3. Craft CMS: Authenticated RCE through Twig sandbox escape
    High CVE-2026-72781 >= 5.0.0-RC1, < 5.10.7, >= 4.0.0-RC1, < 4.18.3 5.10.7, 4.18.3
  4. Craft CMS: Authenticated RCE via `condition.config` JSON cleanse bypass
    High CVE-2026-72778 >= 5.0.0-RC1, < 5.10.6, >= 4.0.0-RC1, < 4.18.2 5.10.6, 4.18.2
  5. Craft CMS: RCE via missing cleanseConfig in FieldsController::actionRenderCardPreview this entry
    High CVE-2026-56382 >= 5.5.0, < 5.9.14 5.9.14
  6. Craft CMS: Potential authenticated Remote Code Execution via referrer redirect
    High CVE-2026-55794 >= 5.9.0, < 5.10.0 5.10.0
  7. Craft CMS: DOM XSS via GitHub issue title in CraftSupport widget
    High CVE-2026-55790 >= 5.0.0-RC1, < 5.9.23, >= 4.0.0-RC1, < 4.17.16 5.9.23, 4.17.16
  8. Craft CMS Vulnerable to Unauthorized Deletion of Destination Folders During Forced Moves
    High CVE-2026-50282 >= 5.0.0-RC1, < 5.9.21, >= 4.0.0-RC1, < 4.17.14 5.9.21, 4.17.14
  9. Craft CMS's mass assignment via id in newAttributes during bulk duplicate overwrites existing elements
    High CVE-2026-50281 >= 5.7.0, < 5.9.21 5.9.21
  10. Craft CMS: Missing peer-permission check in `AssetsController::actionDeleteFolder` allows deletion of other users' assets
    High CVE-2026-50284 >= 5.0.0-RC1, < 5.9.22, >= 4.0.0-RC1, < 4.17.15 5.9.22, 4.17.15
  11. Craft CMS: Authorship spoofing in `entries/save-entry` via pre-check/post-mutation authorization gap
    High CVE-2026-50279 >= 5.0.0-RC1, < 5.9.21 5.9.21
  12. Craft CMS: Blind SSRF and Arbitrary JavaScript Injection via Host Header Poisoning in actionResourceJs
    Critical CVE-2026-55791 >= 5.0.0-RC1, < 5.10, >= 4.0.0-RC1, < 4.18 5.10, 4.18
  13. Craft CMS's Missing Volume Permission Check in AssetsController::actionShowInFolder Allows Information Disclosure
    High CVE-2026-44012 >= 5.0.0-RC1, < 5.9.18 5.9.18
  14. Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior
    High CVE-2026-44011 >= 4.0.0, < 4.17.12, >= 5.0.0, < 5.9.18 4.17.12, 5.9.18
  15. Craft CMS's Missing Authorization in GraphQL Address Resolver Allows Cross-Scope PII Disclosure
    High CVE-2026-44010 >= 5.0.0, < 5.9.18, >= 4.0.0, < 4.17.12 5.9.18, 4.17.12
  16. Craft CMS is Vulnerable to Authenticated Remote Code Execution via Malicious Attached Behavior
    High CVE-2026-33157 >= 5.6.0, < 5.9.13 5.9.13
  17. Craft CMS Vulnerable to Privilege Escalation/Bypass through UsersController->actionImpersonateWithToken()
    High CVE-2026-32267 >= 4.0.0-RC1, < 4.17.6, >= 5.0.0-RC1, < 5.9.12 4.17.6, 5.9.12
  18. Craft CMS vulnerable to behavior injection RCE ElementIndexesController and FieldsController
    High CVE-2026-32264 >= 4.0.0-RC1, < 4.17.5, >= 5.0.0-RC1, < 5.9.11 4.17.5, 5.9.11
  19. Craft CMS vulnerable to behavior injection RCE via EntryTypesController
    High CVE-2026-32263 >= 5.6.0, < 5.9.11 5.9.11
  20. CraftCMS has an RCE vulnerability via relational conditionals in the control panel
    High CVE-2026-31857 >= 5.0.0-RC1, < 5.9.9, >= 4.0.0-beta.1, < 4.17.4 5.9.9, 4.17.4
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