CVE-2026-100858

heym before 0.0.109 contains a server-side request forgery vulnerability in the Slack, Discord, and Crawler workflow nodes. These nodes issue HTTP requests to URLs taken from user-created credentials (webhook_url / flaresolverr_url) using an unguarded HTTP client, bypassing the SSRF egress guard that already protects the HTTP, WebSocket, and MCP nodes; the credential API validates only that the URL is non-empty. Any registered user can create a credential pointing at an internal address and execute a workflow, causing the backend to reach loopback, private, link-local, or cloud-metadata endpoints and return the full response body in the node output (non-blind SSRF).

• https://github.com/heymrun/heym/security/advisories/GHSA-39j3-6x3x-8rcr
• https://www.vulncheck.com/advisories/heym-before-0.0.109-server-side-request-forgery-via-workflow-nodes
• https://github.com/heymrun/heym/security/advisories/GHSA-39j3-6x3x-8rcr