Ubuntu: USN-6363-1 (CVE-2023-38039): curl vulnerability

When curl retrieves an HTTP response, it stores the incoming headers so that
they can be accessed later via the libcurl headers API.

However, curl did not have a limit in how many or how large headers it would
accept in a response, allowing a malicious server to stream an endless series
of headers and eventually cause curl to run out of heap memory.