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CVE-2026-21881

CRITICAL

9.1

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.

CVE Details

CVSS v3.1 Score9.1

SeverityCRITICAL

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/8/2026

Last Modified1/20/2026

Sourcenvd

Honeypot Sightings0

Affected Products

kanboard:kanboard

Weaknesses (CWE)

CWE-287

References

https://github.com/kanboard/kanboard/commit/7af6143e2ad25b5c15549cca8af4341c7ac4e2fc(security-advisories@github.com)

https://github.com/kanboard/kanboard/releases/tag/v1.2.49(security-advisories@github.com)

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

https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739w(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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