CVE-2022-42915

curl before 7.86.0 has a double free. If curl is told to use an HTTP proxy
for a transfer with a non-HTTP(S) URL, it sets up the connection to the
remote server by issuing a CONNECT request to the proxy, and then tunnels
the rest of the protocol through. An HTTP proxy might refuse this request
(HTTP proxies often only allow outgoing connections to specific port
numbers, like 443 for HTTPS) and instead return a non-200 status code to
the client. Due to flaws in the error/cleanup handling, this could trigger
a double free in curl if one of the following schemes were used in the URL
for the transfer: dict, gopher, gophers, ldap, ldaps, rtmp, rtmps, or
telnet. The earliest affected version is 7.77.0.

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