CVE-2026-21881
Kanboard is Vulnerable to Reverse Proxy Authentication Bypass
- State
- Published
- Severity
- 9.1 Critical
- Published
- Jan 8, 2026
- Updated
- Jan 8, 2026
- Reserved
- Jan 5, 2026
Description
Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled. The application blindly trusts HTTP headers for user authentication without verifying the request originated from a trusted reverse proxy. An attacker can impersonate any user, including administrators, by simply sending a spoofed HTTP header. This issue is fixed in version 1.2.49.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | GitHub_M |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
kanboardkanboard |
|
References
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