heym before version 0.0.109 contains an SSRF vulnerability affecting the Slack, Discord, and Crawler workflow nodes. These nodes issue HTTP requests to URLs derived from user-created credentials (webhook_url / flaresolverr_url) using an unguarded HTTP client that bypasses the existing SSRF egress guard protecting other nodes. The credential API only validates that the URL is non-empty, enabling any registered user to create a credential pointing to internal network addresses such as loopback, private, link-local, or cloud metadata endpoints. When a workflow executes, the backend sends requests to these internal endpoints and returns the full response body in the node output, resulting in a non-blind SSRF vulnerability.

An attacker with a registered user account can exploit this vulnerability to make the backend server send HTTP requests to internal or cloud metadata endpoints that are normally inaccessible. This can lead to unauthorized disclosure of sensitive internal information. The CVSS v3.1 score is 6.8 (High), reflecting high confidentiality and integrity impact with no availability impact.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict user permissions to prevent untrusted users from creating or modifying credentials that contain URLs used by the Slack, Discord, and Crawler workflow nodes. Monitor for unusual workflow executions that may indicate exploitation attempts.