CVE-2026-71217
Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion
- Published
- Aug 11, 2026
- Updated
- Aug 31, 2026
- Assigning CNA
- redhat
- Evidence observed
- Sep 20, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HLow · next 30 days
- Percentile
- 46.8%
- Model date
- Sep 20, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
1Python PoC demonstrating CVE-2026-71217, a resource-exhaustion denial-of-service in iperf3 3.16, with Docker setup and crafted stream attack.
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