CVE-2026-21881

9.1 CRITICAL
Published: January 08, 2026 Modified: January 20, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/kanboard/kanboard/releases/tag/v1.2.49
Source: security-advisories@github.com
Release Notes
https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w
Source: security-advisories@github.com
Exploit Vendor Advisory
https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.1 / 10.0
EPSS (Exploit Probability)
0.3%
55th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

kanboard