VulnerabilityAnalyzed

CVE-2026-28781

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.

HIGH 7.1EPSS 0.33%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 7.1 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.33% probability · 26th percentile
CISA KEV: Not listed
Weakness: CWE-639, CWE-915
Affected: craftcms/craft cms
Source: security-advisories@github.com

References

https://github.com/craftcms/cms/commit/830b403870cd784b47ae42a3f5a16e7ac2d7f5a8Patch
https://github.com/craftcms/cms/commit/c6dcbdffaf6ab3ffe77d317336684d83699f4542Patch
https://github.com/craftcms/cms/security/advisories/GHSA-2xfc-g69j-x2mpExploit, Patch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.