CVE-2026-39912: CEDAR2025 Xboard

Critical severity, CVSS 9.1. EPSS: 0.7% chance of exploitation in the next 30 days.

V2Board 1.6.1 through 1.7.4 and Xboard through 0.1.9 expose authentication tokens in HTTP response bodies of the loginWithMailLink endpoint when the login_with_mail_link_enable feature is active. Unauthenticated attackers can POST to the loginWithMailLink endpoint with a known email address to receive the full authentication URL in the response, then exchange the token at the token2Login endpoint to obtain a valid bearer token with complete account access including admin privileges.

Affected products

• CEDAR2025 Xboard: up to and including 0.1.9
• v2board v2board: from 1.6.1, up to and including 1.7.4

Published 2026-04-09. Last modified 2026-07-14.