Lightdash Scheduled Delivery Webhook URLs Are Not Validated, Allowing Server-Side Request Forgery

Summary

Lightdash stores the webhook URL supplied with a scheduled delivery and later posts to it from sendWebhook in packages/backend/src/clients/GoogleChat/GoogleChatClient.ts and in packages/backend/src/clients/MicrosoftTeams/MicrosoftTeamsClient.ts. In affected versions both call fetch on the stored URL directly. The validatePublicHttpUrl helper in packages/backend/src/utils/ssrfProtection.ts, used for MCP server URLs, is not applied on either path, and the webhook fields carry no server-side URL constraint. A user able to create or trigger a scheduled delivery can therefore direct the server to issue POST requests to private, loopback and link-local addresses, including cloud metadata endpoints, and can distinguish reachable internal services from unreachable ones through the resulting errors. The upstream response is never returned to the requester; on a failure status its body is written to the server log instead. Version 1.146.4 routes both clients through postSchedulerWebhook from packages/backend/src/utils/schedulerWebhookValidation rather than calling fetch directly.