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CWE-201Weakness · CWE-201

CVE-2026-39912

CRITICAL · 9.1 CVSS v3.1 Published 2026-04-09
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix Moderate confidence

Xboard version newer than 0.1.9 (or latest release containing commit 121511523f04882ec0c7447acd9b8ebcb8a47957)

  1. 1. Identify the current Xboard installation version by checking the application or git tag (likely 0.1.9 or earlier)
  2. 2. Clone or navigate to the Xboard repository: https://github.com/cedar2025/Xboard
  3. 3. Fetch the latest commits from the remote repository
  4. 4. Locate the commit 121511523f04882ec0c7447acd9b8ebcb8a47957 and verify the fix - the patch should prevent authentication URLs/tokens from being exposed in the loginWithMailLink endpoint response
  5. 5. Apply the fix by checking out the commit or pulling the latest code that includes the patch
  6. 6. Alternatively, upgrade to the latest Xboard release that includes the security fix (newer than 0.1.9)
  7. 7. For V2Board installations (1.6.1-1.7.4), check if V2Board has corresponding patches or consider migrating to Xboard if V2Board is no longer maintained
  8. 8. After applying the fix, test the loginWithMailLink endpoint to confirm tokens are no longer exposed in the response body
Caveat Ensure compatibility with existing V2Board integration if using Xboard as a backend; review any API changes in newer versions

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-39912 in production — separate from our analysis above.

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