CVE-2026-21881

Published: Jan 8, 2026Modified: Jun 17, 2026

9.1

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitability: 3.9 / Impact: 5.2

Source: security-advisories@github.com (Secondary)

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.

Affected (1)

Products: Kanboard: Kanboard

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Kanboard Kanboard	Before 1.2.49

Related CWEs

Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

References (4)

https://github.com/kanboard/kanboard/commit/7af6143e2ad25b5c15549cca8af4341c7ac4e2fc

Source: security-advisories@github.com

Patch

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

ExploitVendor Advisory

https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

ExploitVendor Advisory

Timeline

No history available yet.