The remote host is vulnerable to a buffer overflow.
The remote host is using a version of curl (or libcurl) that is vulnerable to a remote buffer overflows. To exploit, an attacker would have to set up a rogue web server and entice a curl user into browsing to the malicious server. Upon successful exploitation, the attacker would be able to execute arbitrary commands with the rights of the web server.
Upgrade or patch according to vendor recommendations.