CVE-2026-39912

Critical

Description

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.

SeverityCritical

CVSS9.1

Exploit probability—

Product

V2board

PublishedApr 9, 2026

First seenApr 9, 2026

Weakness typeCWE-201CWE-201

How to fix

Patches

github.com/cedar2025/Xboard/commit/121511523f04882ec0c7447acd9b8ebcb8a47957

Affected products

Product	Affected versions	Fixed in
v2board v2board	1.6.1 ≤ v ≤ 1.7.4, bdb10bed32c5f37df2f0872c3cb354e9b7a293bd ≤ v ≤ 0ca47622a50116d0ddd7ffb316b157afb57d25e8	—
cedar2025 Xboard	v ≤ 0.1.9	—

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