NocoDB is software for building databases as spreadsheets. Prior to 2026.05.1, with NC_SECURE_ATTACHMENTS=true, an authenticated uploader could deliver .html or .svg attachments that the browser rendered inline from the NocoDB origin instead of forcing a download. The signed attachment handler stored response-header overrides under PascalCase keys (ResponseContentDisposition, ResponseContentType) while the controller that served the file read them under lowercase-hyphen names (response-content-disposition). The mismatch dropped the Content-Disposition: attachment header, leaving Express to auto-render .html, .svg, and similar inline. This vulnerability is fixed in 2026.05.1.

Affected: npm: nocodb

### Summary With `NC_SECURE_ATTACHMENTS=true`, an authenticated uploader could deliver `.html` or `.svg` attachments that the browser rendered inline from the NocoDB origin instead of forcing a download.

### Details The signed attachment handler stored response-header overrides under PascalCase keys (`ResponseContentDisposition`, `ResponseContentType`) while the controller that served the file read them under lowercase-hyphen names (`response-content-disposition`). The mismatch dropped the `Content-Disposition: attachment` header, leaving Express to auto-render `.html`, `.svg`, and similar inline. The fix corrects the key case and additionally forces `Content-Disposition: attachment` and `Content-Type: application/octet-stream` for any MIME type not on the preview allowlist.

### Impact Stored Cross-Site Scripting in the NocoDB origin from inline-rendered uploads. Script executing in the victim's browser can read the auth JWT from `localStorage`. Exploitation requires authenticated upload permission and the secure-attachment mode to be enabled.

### Credit This issue was reported by [@bugbunny-research](https://github.com/bugbunny-research). It was independently reported by [@DavidCarliez](https://github.com/DavidCarliez).