{"cve":"CVE-2026-21881","nvd":{"published":"2026-01-08T02:15:53.803","modified":"2026-06-17T10:19:04.960","status":"Analyzed","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-287"],"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"],"products":["kanboard:kanboard"],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2026-21881","score":0.00486,"percentile":0.41901,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}