The vulnerability in heym versions before 0.0.91 involves storing and exposing multiple capability secrets in plaintext. Webhook header-auth values are returned in cleartext via GET /api/workflows/{id} and stored unsanitized in execution history. MCP API keys are stored in plaintext columns, returned in configuration listings, and accepted via query strings, causing potential leakage through logs and Referer headers. Portal session tokens are stored and validated by plaintext equality with a 168-hour TTL. Workflow execution JWTs are stored fully and re-listed via API. Discord interaction tokens and global variables are also stored in plaintext within execution history. This exposure allows users with read access or access to backups/logs to recover secrets and replay them to execute workflows or act as the secret owner.

Confidentiality of multiple sensitive secrets is compromised, including API keys, session tokens, and JWTs. This enables unauthorized users with read access or access to backups/logs to retrieve these secrets and potentially execute workflows or impersonate legitimate users. The vulnerability does not impact integrity or availability directly but poses a significant confidentiality risk.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict read access to workflows, execution history, backups, and logs to trusted users only to minimize exposure of plaintext secrets.