CVE-2026-28781 Craft Affected by Entries Authorship Spoofing via Mass Assignment

What is CVE-2026-28781?

CVE-2026-28781 is a high-severity vulnerability in Craftcms Craft Cms, published on 4 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

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.

Weakness: CWE-915, CWE-639

Which versions are affected by CVE-2026-28781?

4 open source packages ship an affected version, including craftcms/cms. It affects 1 product.

Products include Craftcms Craft Cms.

How do I fix CVE-2026-28781?

Upgrade craftcms/cms to a fixed version for your release line: 4.17.0-beta.1 or 5.9.0-beta.1.

Is CVE-2026-28781 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-28781 exists.

Other vulnerabilities in Craftcms Craft Cms

• CVE-2025-32432 Craft CMS Code Injection Exploited Critical 10.0
• CVE-2024-56145 Craft CMS Code Injection Exploited Critical 9.3
• CVE-2025-23209 Craft CMS Code Injection Exploited High 8.1
• CVE-2025-35939 Craft CMS External Control of Assumed-Immutable Web Parameter Exploited Medium 6.9
• CVE-2023-41892 Craft CMS Remote Code Execution vulnerability Critical 10.0

All Craftcms Craft Cms vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-2xfc-g69j-x2mp.