v2board/Xboard WithMailLink Endpoint login_with_mail_link_enable insertion of sensitive information into sent data

CVSS Meta Temp Score
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CTI Interest Score
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8.0$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in v2board and Xboard. This impacts the function login_with_mail_link_enable of the component WithMailLink Endpoint. Performing a manipulation results in insertion of sensitive information into sent data. This vulnerability was named CVE-2026-39912. The attack may be initiated remotely. There is no available exploit. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in v2board and Xboard (affected version not known). This affects the function login_with_mail_link_enable of the component WithMailLink Endpoint. The manipulation with an unknown input leads to a insertion of sensitive information into sent data vulnerability. CWE is classifying the issue as CWE-201. The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was presented by Valentin Lobstein. The advisory is shared at chocapikk.com. This vulnerability is uniquely identified as CVE-2026-39912 since 04/07/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1592 for this issue.

Applying the patch 121511523f04882ec0c7447acd9b8ebcb8a47957 is able to eliminate this problem. The bugfix is ready for download at github.com.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Insertion of sensitive information into sent data
CWE: CWE-201 / CWE-200 / CWE-284
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: 121511523f04882ec0c7447acd9b8ebcb8a47957

Timelineinfo

04/07/2026 CVE reserved
04/09/2026 +2 days Advisory disclosed
04/09/2026 +0 days VulDB entry created
04/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: chocapikk.com
Researcher: Valentin Lobstein
Status: Confirmed

CVE: CVE-2026-39912 (🔒)
GCVE (CVE): GCVE-0-2026-39912
GCVE (VulDB): GCVE-100-356673

Entryinfo

Created: 04/09/2026 22:07
Changes: 04/09/2026 22:07 (77)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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