CVE-2026-100858 HIGH

CVE-2026-100858: heym before 0.0.109 Server-Side Request Forgery via Workflow Nodes

Vendor Heymrun
Product heym
Weakness CWE-918 · SSRF
Published September 27, 2026
Last update September 27, 2026

CVSS base score

7.6/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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).

Key dates

02Disclosure timeline

September 27, 2026 CVE published

Related vulnerabilities

04Related CVE