CVE-2026-21881

9.1 criticalEPSS 0.5%

Critical (9.1) in kanboard kanboard. EPSS 0.5% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

9.1 critical

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

EPSS: 0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-31)
CWE: CWE-287
Published: 2026-01-08
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

kanboard:kanboard

References

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

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