SSRF in Heymrun Heym
CVE-2026-100859
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 17.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-39qx-wp7x-69rq) (vendor-advisory)
- VulnCheck Advisory: Heym before 0.0.106 Credential Exfiltration via URL Override (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100859?
- CVE-2026-100859 is a medium-severity vulnerability in Heymrun Heym, classified under Server-Side Request Forgery (SSRF). CVSS score: 6.5/10. Published 2026-09-27.
- How severe is CVE-2026-100859?
- Medium severity. CVSS v3 base score is 6.5 out of 10.