Datasette 1.0 alpha series leaks names of databases and tables to unauthenticated users. I found and fixed a security vulnerability in the Datasette 1.0 alpha series, described in this GitHub security advisory.
The vulnerability allowed unauthenticated users to see the names of the databases and tables in an otherwise private Datasette instance—though not the actual table contents.
The fix is now shipped in Datasette 1.0a4.
The vulnerability affected Datasette Cloud as well, but thankfully I was able to analyze the access logs and confirm that no unauthenticated requests had been made against any of the affected endpoints.