CVE-2026-102253

iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS

CVE-2026-102253 is fixed in 5 products on 1 platform, first by FEDORA-2026-AF72C5C990, released October 4, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.5

Important

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0043

37th percentile

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.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
iperf · opensuse-leap 16.0	3.21-160000.1.1	OPENSUSE-SU-2026:22090-1	Nov 7, 2026
iperf · sles 15.7	3.22-150000.3.18.1	SUSE-SU-2026:4678-1	Nov 7, 2026
iperf · sles 16.0	3.21-160000.1.1	SUSE-SU-2026:24234-1	Nov 7, 2026
iperf3 · Debian 14	3.22-0.1	DEBIAN-CVE-2026-102253	Oct 5, 2026
iperf3 · Fedora 43	3.22-2.fc43	FEDORA-2026-AF72C5C990	Oct 4, 2026
iperf3 · RHEL 10	3.17.1-6.el10_2.2	RHSA-2026:88207	Oct 24, 2026
iperf3 · almalinux 10	3.17.1-6.el10_2.2	ALSA-2026:88207	Nov 7, 2026
iperf3 · ol 10	0:3.17.1-6.el10_2.2	ELSA-2026-88207	Nov 7, 2026
iperf3 · rocky 10	0:3.17.1-6.el10_2.2	RLSA-2026:88207	Nov 7, 2026
iperf3-debuginfo · Fedora 43	3.22-2.fc43	FEDORA-2026-AF72C5C990	Oct 4, 2026
iperf3-debugsource · Fedora 43	3.22-2.fc43	FEDORA-2026-AF72C5C990	Oct 4, 2026
iperf3-devel · Fedora 43	3.22-2.fc43	FEDORA-2026-AF72C5C990	Oct 4, 2026

Details

Published
September 29, 2026
Weakness
Loop with Unreachable Exit Condition ('Infinite Loop')
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102253

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