QAuthenticator doesn't check if algorithm is supported

WEB server supports Digest authentication with SHA-256 and MD5. It's reply contains two www-authenticate (challenges? not sure about terminology):

www_authenticate: Digest algorithm=SHA-256, realm=...
www_authenticate: Digest algorithm=MD5, realm=...

QAuthenticator takes first entry and sends request with
Digest username=..., algorithm=SHA-256, ...

Of course, it fails.
By the way, QNetworkReply argument in authenticationRequired slot contains no headers at all, so I had to capture packets with Wireshark to figure out what's happening.