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 .
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
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/heymrun/heym/security/advisories/GHSA-39qx-wp7x-69rq (vendor-advisory)
- www.vulncheck.com/advisories/heym-before-0.0.106-credential-exfiltration-via-ur… (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.