Vulnerability · Published Mar 4, 2026 · Assigned by GitHub_M
CVE-2026-28781Craft Affected by Entries Authorship Spoofing via Mass Assignment
High 7.1
In plain English
A high-severity authorization bypass via user-controlled key in cms from craftcms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Craft is a content management system (CMS). Prior to 4.17.0-beta.1 and 5.9.0-beta.1, the entry creation process allows for Mass Assignment of the authorId attribute. A user with "Create Entries" permission can inject the authorIds[] (or authorId) parameter into the POST request, which the backend processes without verifying if the current user is authorized to assign authorship to others. Normally, this field is not present in the request for users without the necessary permissions. By manually adding this parameter, an attacker can attribute the new entry to any user, including Admins. This effectively "spoofs" the authorship. This vulnerability is fixed in 4.17.0-beta.1 and 5.9.0-beta.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | craftcms/cms | 5.9.0-beta.1 | GHSA-2xfc-g69j-x2mp |
| Packagist | craftcms/cms | 4.17.0-beta.1 | GHSA-2xfc-g69j-x2mp |
Affected products (as reported)
Weakness: CWE-639, CWE-915 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N