CyberSecBulletin
CVE-2026-39912NVD status: Deferred

v2board: Insertion of Sensitive Information Into Sent Data

Published Updated By the CyberSecBulletin desk

CVE-2026-39912 is a critical-severity insertion of sensitive information into sent data vulnerability in v2board, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected v2board versions: 1.6.1 through 1.7.4; bdb10bed32c5f37df2f0872c3cb354e9b7a293bd through 0ca47622a50116d0ddd7ffb316b157afb57d25e8. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of v2board you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
V2boardv2board1.6.1 through 1.7.4; bdb10bed32c5f37df2f0872c3cb354e9b7a293bd through 0ca47622a50116d0ddd7ffb316b157afb57d25e8Not stated
Cedar2025Xboard0.1.9 and earlierNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (vulncheck.com).

Scoring systemScoreSeverityScored by
CVSS 4.09.1CriticalCNA (vulncheck.com)
CVSS 3.19.1CriticalCNA (vulncheck.com)

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Insertion of Sensitive Information Into Sent Data

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

How developers prevent this class of flaw

  • Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
  • Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere. Any information that is not necessary to the functionality should be removed in order to lower both the overhead and the possibility of security sensitive data being sent.
  • Setup default error messages so that unexpected errors do not disclose sensitive information.

More Insertion of Sensitive Information Into Sent Data vulnerabilities (CWE-201)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in v2board

All v2board vulnerabilities

Recent Insertion of Sensitive Information Into Sent Data vulnerabilities

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