CRITICAL🇵🇱 Wersja polska

CVE-2026-21881

CVSS 9.1v3.1pub. 2026-01-08upd. 2026-01-20

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.

🤖 AI Analysis
How it works

When the REVERSE_PROXY_AUTH feature is enabled, the Kanboard application trusts HTTP headers passed in the request and uses them to identify the user. The problem is that the application does not verify whether the request actually comes from a trusted reverse proxy. An attacker can therefore send an HTTP request directly with an arbitrarily crafted header pointing to a selected user (e.g., an administrator) and gain full access to their account.

Impact

A remote attacker, without authentication, can assume the identity of any system user — including an administrator — gaining full access to project data and the ability to modify or delete it.

Mitigation & patch

Kanboard should be updated to version 1.2.49, where the vulnerability has been fixed. As a temporary workaround, consider disabling the REVERSE_PROXY_AUTH option until the update is deployed, and restrict application access exclusively from trusted IP addresses at the firewall level.

Who is affected

Kanboard in versions 1.2.48 and earlier when the REVERSE_PROXY_AUTH option is enabled.

Analysis generated by Claude AI (Anthropic) based on NVD data. Always verify with vendor.
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
  • Kanboard

    APP
    Kanboard
    < 1.2.49
🔵
CHECK WITH VENDOR
No clear patch data available. Check vendor references.
Tags
Auth Bypass
CWE
References

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