CVE-2026-39912
Critical · CVSS 9.1V2Board / Xboard — Authentication token exposure in HTTP response body (CWE-201) leading to account takeover
- CVSS
- 9.1
- nvd
- EPSS
- —
- KEV
- No
- Class
- oss containerizable
- CWE-201
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.
Search profile — drives PoC discovery
Ranked PoCs (1) — best first
Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.
- ★ 2
Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.
References
- https://chocapikk.com/posts/2026/xboard-v2board-account-takeover/
- https://github.com/cedar2025/Xboard/blob/1fe6531924cc1ec662a88b9ef725afcf78d660bc/app/Http/Controllers/V1/Passport/AuthController.php#L51
- https://github.com/cedar2025/Xboard/blob/1fe6531924cc1ec662a88b9ef725afcf78d660bc/app/Services/Auth/MailLinkService.php#L49
- https://github.com/cedar2025/Xboard/commit/121511523f04882ec0c7447acd9b8ebcb8a47957
- https://github.com/cedar2025/Xboard/pull/873
- https://github.com/v2board/v2board/blob/0ca47622a50116d0ddd7ffb316b157afb57d25e8/app/Http/Controllers/Passport/AuthController.php#L71
- https://github.com/v2board/v2board/pull/981
- https://www.vulncheck.com/advisories/v2board-xboard-authentication-token-exposure-via-loginwithmaillink
Status: enriched · ingested 2026-07-15T00:00:20.000Z · profiled 2026-07-15T00:30:20.000Z