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.
Fixes and workarounds
Workaround
To mitigate this issue, restrict network access to the `iperf3` server to trusted clients or networks using firewall rules. If the `iperf3` server functionality is not required, disable the `iperf3` service.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat iperf3
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:3.17.1-6.el10_2.1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat iperf3
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:3.5-12.el8_10.1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat iperf3
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:3.9-17.el9_8.1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat iperf3
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/errata/RHSA-2026:61257CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:61389CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:61680CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-71217CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2460984CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://github.com/esnet/iperf/commit/494dd377eca4689672becdf06a85158557db1586CNA: redhat
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