Affected: https://github.com/curl/curl

A malicious server can use the FTP PASV response to trick curl 7.73.0 and earlier into connecting back to a given IP address and port, and this way potentially make curl extract information about services that are otherwise private and not disclosed, for example doing port scanning and service banner extractions.

Affected: Ubuntu:16.04:LTS: curl, Ubuntu:18.04:LTS: curl, Ubuntu:20.04:LTS: curl

Marc Aldorasi discovered that curl incorrectly handled the libcurl CURLOPT_CONNECT_ONLY option. This could result in data being sent to the wrong destination, possibly exposing sensitive information. This issue only affected Ubuntu 20.10. (CVE-2020-8231)

Varnavas Papaioannou discovered that curl incorrectly handled FTP PASV responses. An attacker could possibly use this issue to trick curl into connecting to an arbitrary IP address and be used to perform port scanner and other information gathering. (CVE-2020-8284)

It was discovered that curl incorrectly handled FTP wildcard matchins. A remote attacker could possibly use this issue to cause curl to consume resources and crash, resulting in a denial of service. (CVE-2020-8285)

It was discovered that curl incorrectly handled OCSP response verification. A remote attacker could possibly use this issue to provide a fraudulent OCSP response. (CVE-2020-8286)