CVE-2026-48153: Budibase: SSRF via OAuth2 token endpoint URL reaches internal hosts and cloud metadata

fetchToken in the OAuth2 SDK makes a POST to a builder-supplied URL with plain node-fetch, skipping the blacklist.isBlacklisted check that every other outbound fetch path in the codebase uses. The Joi schema for the OAuth2 URL has no scheme or host restriction. Alice, a builder, points an OAuth2 config at http://169.254.169.254/... or http://127.0.0.1:5984/; the server connects and returns response-body fragments in the validation result.