NocoDB: Missing File Size Enforcement in Upload-by-URL Allows Denial of Service via Disk Exhaustion

Summary

The uploadViaURL path in the v1/v2 attachment API did not enforce NC_ATTACHMENT_FIELD_SIZE against the remote content-length or against the response stream. An authenticated user (Editor+) could direct the server to download arbitrarily large files, exhausting disk space and causing denial of service.

Details

In packages/nocodb/src/services/attachments.service.ts, the HEAD probe read content-length but never compared it to NC_ATTACHMENT_FIELD_SIZE; the subsequent storageAdapter.fileCreateByUrl() performed the download without maxContentLength. The v3 service (v3/data-attachment-v3.service.ts) already enforced the limit, but the v1/v2 endpoints (POST /api/v1/db/storage/upload-by-url, POST /api/v2/storage/upload-by-url) did not.

This is distinct from GHSA-xr7v-j379-34v9 (blind SSRF via HEAD) — same code area, different class.

Impact

• Authenticated DoS via disk exhaustion. Editor role suffices.
• Cascading failures once disk fills: blocked DB writes, log rotation, application crash.

Credit

This issue was reported by @ik0z.