Improper Authentication in Kanboard - CVE-2026-21881
Published: January 7, 2026 / Updated: January 9, 2026
Vulnerability identifier: #VU121017
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-21881
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication process.
The vulnerability exists due to an error when REVERSE_PROXY_AUTH is enabled. A remote attacker can bypass authentication process and gain unauthorized access to the application.
Affected software
Kanboard
How to mitigate CVE-2026-21881
Install updates from vendor's website.
Kanboard - update to 1.2.49