CVE-2026-21881 | THREATINT

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.

PUBLISHED Reserved 2026-01-05 | Published 2026-01-08 | Updated 2026-01-08 | Assigner GitHub_M

CRITICAL: 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Problem types

CWE-287: Improper Authentication

Product status

< 1.2.49

affected

References

github.com/...nboard/security/advisories/GHSA-wwpf-3j4p-739w exploit

github.com/...nboard/security/advisories/GHSA-wwpf-3j4p-739w

github.com/...ommit/7af6143e2ad25b5c15549cca8af4341c7ac4e2fc

github.com/kanboard/kanboard/releases/tag/v1.2.49

cve.org (CVE-2026-21881)

nvd.nist.gov (CVE-2026-21881)

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