Vulnerability Description
Craft CMS is a content management system (CMS). Versions 5.7.0 and above, prior to 5.9.21 contain a mass-assignment flaw in the bulk-duplicate element action. An attacker who is only able to duplicate their own entires can submit an arbitrary id through the newAttributes request parameter. The duplication routine overrides its own id = null reset with that value and writes the attacker's attributes into the victim's existing entry row. ElementsController::beforeAction() pulls the request body into $this->_attributes and rejects requests that ship an id or canonicalId key at the top level, actionBulkDuplicate(), reads a separate newAttributes array and passes it straight through to the service layer. Elements::duplicateElement() clones the source element, sets id to null, and then hands the attacker's array to Craft::configure(), which overwrites the reset id with any numeric value inside $newAttributes. PHP Yii's saveElement() then performs an UPDATE against the row with that primary key instead of an INSERT. The attackers's title, slug, authorId, postDate, and UID land on the victim's entry. safeAttributes() on Entry includes id because the base element model exposes it, so the Collection::only() filter does not strip it. This issue has been fixed in version 5.9.21.
Related Weaknesses (CWE)
References
- https://github.com/craftcms/cms/commit/8f6587c25050bbb6e080d59c71f6bb8932fc8600
- https://github.com/craftcms/cms/security/advisories/GHSA-x5m4-g2cq-52pq
FAQ
What is CVE-2026-50281?
CVE-2026-50281 is a documented vulnerability. Craft CMS is a content management system (CMS). Versions 5.7.0 and above, prior to 5.9.21 contain a mass-assignment flaw in the bulk-duplicate element action. An attacker who is only able to duplicate...
How severe is CVE-2026-50281?
CVSS scoring is not yet available for CVE-2026-50281. Check NVD for updates.
Is there a patch for CVE-2026-50281?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.