CVE-2026-21881CRITICAL 9.1EPSS p34.5%

CVE-2026-21881CVE-2026-21881

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.

Scoring

CVSS 3.19.1 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS0.43% probability of exploitation · percentile 34.5% · 2026-06-18T12:00:27Z
Published2026-01-08
Last modified2026-01-20

Underlying weaknesses· 1

CWE-287

References

  1. https://github.com/kanboard/kanboard/commit/7af6143e2ad25b5c15549cca8af4341c7ac4e2fc
  2. https://github.com/kanboard/kanboard/releases/tag/v1.2.49
  3. https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w
  4. https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w

1

TypeTargetConfidenceTier
WeaknessImproper Authenticationcwe-2870%live

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.