CVE-2026-102253

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductEsnet Iperf3

PublishedSep 29, 2026

First seenSep 29, 2026

Weakness typeCWE-835CWE-835

How to fix

Update

esnet iperf33.22 or later

Patches

github.com/esnet/iperf/releases/tag/3.22

Vendor advisories

github.com/esnet/iperf/blob/master/RELNOTES.md

Affected products

Product	Affected versions	Fixed in
esnet iperf3	3.14 ≤ v < 3.22	3.22

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