iPerf3 before 3.17, when used with OpenSSL before 3.2.0 as a server with RSA authentication, allows a timing side channel in RSA decryption operations. This side channel could be sufficient for an attacker to recover credential plaintext. It requires the attacker to send a large number of messages for decryption, as described in "Everlasting ROBOT: the Marvin Attack" by Hubert Kario.
A flaw was found in iperf, a utility for testing network performance using TCP, UDP, and SCTP. A malicious or malfunctioning client can send less than the expected amount of data to the iperf server, which can cause the server to hang indefinitely waiting for the remainder or until the connection gets closed. This will prevent other connections to the server, leading to a denial of service.