Junglewise Threat Intelligence

CVE-2026-100859: Heym credential exfiltration in credentials test endpoint

CVE-2026-100859 · Severity: medium · CVSS 6.5 · Published 2026-09-27

Technologies: Heymrun Heym. Vendors: Heymrun.

Executive brief

Heym is a credential management platform that allows teams to securely store and share authentication secrets. A flaw in the credential testing endpoint allows a collaborator with legitimate access to a shared credential to steal the credential owner's authentication secret by redirecting the test request to an attacker-controlled server. This enables unauthorized disclosure of sensitive credentials like API tokens and passwords.

Technical details

The POST /api/credentials/test endpoint improperly validates configuration overrides, allowing an authenticated collaborator to merge caller-supplied config (including a malicious base_url) with a shared credential before testing the connection. The endpoint then sends the decrypted credential's authentication secret to the attacker-specified URL via integrations like Jira and Supabase. An attacker must have legitimate shared access to a credential and network access to call the endpoint.

Affected products

  • heymrun Heym before 0.0.106

Timeline

  • 2026-09-05: disclosed: GitHub security advisory published
  • 2026-09-05: patched: Fix released in version 0.0.106

References

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