Flowise before 3.1.0 (npm package flowise, versions 3.0.13 and earlier) uses a weak hardcoded default value 'Secre$t' for the TOKEN_HASH_SECRET environment variable in packages/server/src/enterprise/utils/tempTokenUtils.ts when the variable is not configured. This secret derives the AES-256-CBC key used to encrypt user IDs and workspace IDs in the 'meta' field of JWT tokens. An attacker who knows the default secret can decrypt this metadata to extract internal user and workspace identifiers, and re-encrypt manipulated values such as altered user or workspace IDs. Because the JWT signature is validated separately, decrypting or tampering with this metadata does not by itself grant access, but the disclosure of internal identifiers and possible metadata manipulation could aid privilege escalation or unauthorized data access.