CVE-2026-102253

iperf3 versions prior to 3.22 contains a denial of service vulnerability that allows unauthenticated remote attackers to crash-loop the server's UDP receive worker into an unrecoverable infinite loop by sending a single crafted control-channel parameter message followed by one 16-byte UDP datagram. Attackers can permanently pin the affected per-stream receive thread at approximately 100% CPU usage, rendering the server unusable until forcibly killed with SIGKILL, as the process does not respond to normal control-channel closure.

• https://github.com/esnet/iperf/blob/master/RELNOTES.md
• https://github.com/esnet/iperf/releases/tag/3.22
• https://www.vulncheck.com/advisories/iperf3-udp-receive-worker-infinite-loop-dos