Several issues were discovered in openvpn, a virtual private network application. CVE-2017-7479 It was discovered that openvpn did not properly handle the rollover of packet identifiers. This would allow an authenticated remote attacker to cause a denial-of-service via application crash. CVE-2017-7508 Guido Vranken discovered that openvpn did not properly handle specific malformed IPv6 packets. This would allow a remote attacker to cause a denial-of-service via application crash. CVE-2017-7520 Guido Vranken discovered that openvpn did not properly handle clients connecting to an HTTP proxy with NTLMv2 authentication. This would allow a remote attacker to cause a denial-of-service via application crash, or potentially leak sensitive information like the user"s proxy password. CVE-2017-7521 Guido Vranken discovered that openvpn did not properly handle some x509 extensions. This would allow a remote attacker to cause a denial-of-service via application crash.