Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion
CVE-2026-71217 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-71217, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
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-2026-71217 | Aug 11, 2026 |
| iperf3 · RHEL 10 | 3.17.1-6.el10_2.1 | RHSA-2026:61680 | Sep 2, 2026 |
| iperf3 · RHEL 8 | 0:3.5-12.el8_10.1 | RHSA-2026:61257 | Sep 13, 2026 |
| iperf3 · RHEL 9 | 0:3.9-17.el9_8.1 | RHSA-2026:61389 | Sep 13, 2026 |
| iperf3 · almalinux 10 | 3.17.1-6.el10_2.1 | ALSA-2026:61680 | Aug 31, 2026 |
| iperf3 · almalinux 8 | 3.5-12.el8_10.1 | ALSA-2026:61257 | Aug 31, 2026 |
| iperf3 · almalinux 9 | 3.9-17.el9_8.1 | ALSA-2026:61389 | Aug 31, 2026 |
| iperf3 · amzn 2023 | 3.19.1-1.amzn2023.0.1 | ALAS2023-2026-2070 | Aug 31, 2026 |
| iperf3 · ol 10 | 0:3.17.1-6.el10_2.1 | ELSA-2026-61680-0 | Sep 1, 2026 |
| iperf3 · ol 8 | 0:3.5-12.el8_10.1 | ELSA-2026-61257-0 | Sep 1, 2026 |
| iperf3 · ol 9 | 0:3.9-17.el9_8.1 | ELSA-2026-61389-0 | Sep 1, 2026 |
| iperf3 · rocky 10 | 0:3.17.1-6.el10_2.1 | RLSA-2026:61680 | Sep 1, 2026 |
| iperf3 · rocky 8 | 0:3.5-12.el8_10.1 | RLSA-2026:61257 | Aug 31, 2026 |
| iperf3 · rocky 9 | 0:3.9-17.el9_8.1 | RLSA-2026:61389 | Sep 1, 2026 |
| iperf3-debuginfo · amzn 2023 | 3.19.1-1.amzn2023.0.1 | ALAS2023-2026-2070 | Aug 31, 2026 |
| iperf3-debugsource · amzn 2023 | 3.19.1-1.amzn2023.0.1 | ALAS2023-2026-2070 | Aug 31, 2026 |
| iperf3-devel · amzn 2023 | 3.19.1-1.amzn2023.0.1 | ALAS2023-2026-2070 | Aug 31, 2026 |
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