All vulnerabilities
CVE-2026-102253

iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS

esnet iperf3
Open in ThreatlineRecord JSON
CVSS
8.7High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.43%Chance of exploitation activity in the next 30 days, higher than 36% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in3.22Fixed versionCVE List
Published29 Sep 2026Updated 1 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

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.

Text from CVE List

Affected versions 1

  • iperf3affected: 3.14 before 3.22CVE List

References 3