Improper access control in Joplin Server - CVE-2025-27134
Published: April 30, 2025 / Updated: May 26, 2026
Vulnerability identifier: #VU132298
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-27134
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Joplinapp
Affected software:
Joplin Server
Joplin Server
Detailed vulnerability description
The vulnerability allows a remote user to escalate privileges.
The vulnerability exists due to improper access control in the PATCH /api/users/:id endpoint when handling crafted API requests to update user attributes. A remote user can send a specially crafted request to escalate privileges.
The issue allows a non-admin user to set the is_admin field to 1 for their own account.
How to mitigate CVE-2025-27134
Install security update from vendor's website.