SSRF in Heymrun Heym
CVE-2026-84207
Heym before 0.0.98 fails to apply SSRF egress guards to WebSocket Send and WebSocket Trigger nodes, allowing authenticated users to connect to internal services. Attackers can craft workflow nodes with arbitrary URLs and headers to reach internal services and read responses from the WebSocket Trigger node.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (26.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/heymrun/heym (product)
- github.com/heymrun/heym/security/advisories/GHSA-mqw6-g845-w596 (vendor-advisory)
- github.com/heymrun/heym/commit/540aade7c7495295062f32f4dfd0d6805f066f0c (patch)
- github.com/heymrun/heym/releases/tag/v0.0.98 (release-notes)
- github.com/heymrun/heym/blob/v0.0.97/backend/app/services/websocket_utils.py (technical-description)
- github.com/heymrun/heym/blob/v0.0.97/backend/app/services/websocket_trigger_ser… (technical-description)
- www.vulncheck.com/advisories/heym-before-0.0.98-ssrf-via-websocket-endpoints (third-party-advisory)
Frequently asked questions
- What is CVE-2026-84207?
- CVE-2026-84207 is a medium-severity vulnerability in Heymrun Heym, classified under Server-Side Request Forgery (SSRF). CVSS score: 5.4/10. Published 2026-09-01.
- How severe is CVE-2026-84207?
- Medium severity. CVSS v3 base score is 5.4 out of 10.