vulnerability / NVI-00007709 / Revision 3
Craft CMS's mass assignment via id in newAttributes during bulk duplicate overwrites existing elements
GitHub lists this reviewed advisory for craftcms/cms. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
0.429%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.37172. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
craftcms/cms
source listed>= 5.7.0, < 5.9.21
## Summary There is a mass-assignment flaw in the bulk-duplicate element action. Alice, holding only the permission to duplicate an entry she owns, submits an arbitrary `id` through the `newAttributes` request parameter. The duplication routine overrides its own `id = null` reset with that value and writes Alice’s attributes into Bob’s existing entry row. ## Details `ElementsController::beforeAction()` (`src/controllers/ElementsController.php:119-124`) pulls the request body into `$this->_attributes` and rejects requests that ship an `id` or `canonicalId` key at the top level: ```php $this->_attributes = $this->request->getBodyParams(); // No funny business if (isset($this->_attributes['id']) || isset($this->_attributes['canonicalId'])) { throw new BadRequestHttpException('Changing an element’s ID is not allowed.'); } ``` The check inspects only the top-level payload. `actionBulkDuplicate()` (`src/controllers/ElementsController.php:1708-1749`) reads a separate `newAttributes` array and passes it straight through to the service layer: ```php $elementInfo = $this->request->getRequiredBodyParam('elements'); $newAttributes = $this->request->getRequiredBodyParam('newAttribute
craftcms/cms
source listedECOSYSTEM: introduced 5.7.0; fixed 5.9.21
## Summary There is a mass-assignment flaw in the bulk-duplicate element action. Alice, holding only the permission to duplicate an entry she owns, submits an arbitrary `id` through the `newAttributes` request parameter. The duplication routine overrides its own `id = null` reset with that value and writes Alice’s attributes into Bob’s existing entry row. ## Details `ElementsController::beforeAction()` (`src/controllers/ElementsController.php:119-124`) pulls the request body into `$this->_attributes` and rejects requests that ship an `id` or `canonicalId` key at the top level: ```php $this->_attributes = $this->request->getBodyParams(); // No funny business if (isset($this->_attributes['id']) || isset($this->_attributes['canonicalId'])) { throw new BadRequestHttpException('Changing an element’s ID is not allowed.'); } ``` The check inspects only the top-level payload. `actionBulkDuplicate()` (`src/controllers/ElementsController.php:1708-1749`) reads a separate `newAttributes` array and passes it straight through to the service layer: ```php $elementInfo = $this->request->getRequiredBodyParam('elements'); $newAttributes = $this->request->getRequiredBodyParam('newAttribute
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 5.9.21 for craftcms/cms. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-x5m4-g2cq-52pq ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-x5m4-g2cq-52pq ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-50281 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.