CVE-2026-100859
Received Received - Intake

Credential Exfiltration in Heym via Config Override

Publication date: 2026-09-27

Last updated on: 2026-09-27

Assigner: VulnCheck

Description
Heym before 0.0.106 contains a credential exfiltration vulnerability in the POST /api/credentials/test endpoint that allows collaborators with shared credential access to exfiltrate the credential owner's secret. Attackers can override the destination URL in the config parameter to cause the server to send decrypted authentication secrets to attacker-controlled endpoints.

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Meta Information

Published
2026-09-27
Last Modified
2026-09-27
Generated
2026-09-27
AI Q&A
2026-09-27
EPSS Evaluated
N/A
NVD
CVE-2026-100859
EUVD
EUVD-2026-87824

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
heymrun heym to 0.0.106 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

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Executive Summary

Heym before version 0.0.106 has a credential exfiltration vulnerability in the POST /api/credentials/test endpoint. Collaborators with shared credential access can override the destination URL in the config parameter to exfiltrate the credential owner's secret. The server decrypts and sends authentication secrets to attacker-controlled endpoints.

Detection Guidance

Check if your heym application version is below 0.0.106 by running: heym --version. Monitor network traffic for unexpected outbound connections from the heym server, especially to unknown endpoints. Inspect logs for POST requests to /api/credentials/test with modified config parameters.

Impact Analysis

If you use Heym versions before 0.0.106, attackers with shared credential access could steal your decrypted authentication secrets. This could lead to unauthorized access to your systems, data breaches, or further exploitation of your infrastructure.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection requirements and HIPAA's safeguards for protected health information. Organizations may face compliance violations, fines, or legal consequences if exploited.

Mitigation Strategies

Upgrade heym to version 0.0.106 or later immediately. Restrict access to the /api/credentials/test endpoint to authorized users only. Review and audit shared credentials for any signs of unauthorized access or exfiltration attempts.

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