Authentication Bypass Vulnerability in Kanboard Project Management Software

CVE-2026-21881

What is CVE-2026-21881?

Kanboard, a popular project management tool utilizing Kanban methodology, is susceptible to an authentication bypass vulnerability when the REVERSE_PROXY_AUTH feature is enabled. This flaw arises because the application fails to validate whether HTTP headers originate from a trusted reverse proxy, allowing potential attackers to send falsified HTTP headers. This loophole enables them to impersonate any user, including administrative accounts, posing serious security risks. Users are encouraged to upgrade to version 1.2.49, which addresses this issue.

References