Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Kanboard | Kanboard | < 1.2.49 |
Related Weaknesses (CWE)
References
- https://github.com/kanboard/kanboard/commit/7af6143e2ad25b5c15549cca8af4341c7ac4Patch
- https://github.com/kanboard/kanboard/releases/tag/v1.2.49Release Notes
- https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739wExploitVendor Advisory
- https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739wExploitVendor Advisory
FAQ
What is CVE-2026-21881?
CVE-2026-21881 is a vulnerability with a CVSS score of 9.1 (CRITICAL). 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 b...
How severe is CVE-2026-21881?
CVE-2026-21881 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-21881?
Check the references section above for vendor advisories and patch information. Affected products include: Kanboard Kanboard.