CVE-2026-39912Public exploitNetwork attack vector

Account takeover via returned magic-link token

Published Apr 9, 2026 · Updated Apr 9, 2026

Authentication token exposure in V2Board 1.6.1 through 1.7.4 and Xboard through 0.1.9 allows remote attackers to take over accounts. The loginWithMailLink flow returns the full magic-login URL and its temporary verification token in the HTTP response instead of limiting delivery to email. When login_with_mail_link_enable is active and a registered email address is known, token2Login exchanges the leaked token for a bearer token with the target account's privileges, including administrator access.

CVSS severity9.1
Critical
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication token exposure in V2Board 1.6.1 through 1.7.4 and Xboard through 0.1.9 allows remote attackers to take over accounts. The loginWithMailLink flow returns the full magic-login URL and its temporary verification token in the HTTP response instead of limiting delivery to email. When login_with_mail_link_enable is active and a registered email address is known, token2Login exchanges the leaked token for a bearer token with the target account's privileges, including administrator access.

The record

CVE
CVE-2026-39912
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
cedar2025
Product
Xboard
Classifications
CWE-201, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=0.1.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

cedar2025 · Xboardversion=0 <=0.1.9
V2Board · V2Boardversion=1.6.1 <=1.7.4; version=bdb10bed32c5f37df2f0872c3cb354e9b7a293bd <=0ca47622a50116d0ddd7ffb316b157afb57d25e8

Published CVSS scores

9.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-201Insertion of Sensitive Information Into Sent Data
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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