When asked to use a `.netrc` file for credentials **and** to follow HTTP
redirects, curl could leak the password used for the first host to the
followed-to host under certain circumstances.
This flaw only manifests itself if the netrc file has a `default` entry that
omits both login and password. A rare circumstance.
When libcurl is asked to perform automatic gzip decompression of
content-encoded HTTP responses with the `CURLOPT_ACCEPT_ENCODING` option,
**using zlib 1.2.0.3 or older**, an attacker-controlled integer overflow would
make libcurl perform a buffer overflow.
When asked to both use a `.netrc` file for credentials and to follow HTTP
redirects, curl could leak the password used for the first host to the
followed-to host under certain circumstances.
This flaw only manifests itself if the netrc file has an entry that matches
the redirect target hostname but the entry either omits just the password or
omits both login and password.