CVE-2026-71217

Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion

A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as `parallel` and `len`, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server.

Affected

Red Hat · Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 8 · Red Hat Enterprise Linux 9 · Red Hat Enterprise Linux 7

CVSS v3.1 REDHAT

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.64% chance of exploitation in the next 30 days, 49th percentile

Published

2026-08-11

Updated

2026-08-31

Proof-of-concept exploits (1)

• Reelix/CVE-2026-71217-PoC1★ · 2026-09-20

References

• CVE Record
• NVD entry