Improper access control in Grav CMS - CVE-2026-42844
Published: May 5, 2026
Vulnerability identifier: #VU130089
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42844
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Grav CMS
Affected software:
Grav CMS
Grav CMS
Detailed vulnerability description
The vulnerability allows a remote user to escalate privileges.
The vulnerability exists due to improper access control in the /api/v1/blueprint-upload endpoint when handling blueprint upload requests with caller-controlled destination and scope values. A remote user can upload a crafted YAML account file into user/accounts/ to escalate privileges.
Exploitation requires an authenticated API account with the api.media.write permission.
How to mitigate CVE-2026-42844
Install security update from vendor's website.