CVE-2026-21881
Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.49% probability · 41th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- kanboard/kanboard
- Source
- security-advisories@github.com
References
- https://github.com/kanboard/kanboard/commit/7af6143e2ad25b5c15549cca8af4341c7ac4e2fcPatch
- https://github.com/kanboard/kanboard/releases/tag/v1.2.49Release Notes
- https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739wExploit, Vendor Advisory
- https://github.com/kanboard/kanboard/security/advisories/GHSA-wwpf-3j4p-739wExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.