CVE-2026-71217

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

Published Aug 11, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor 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.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Iperf3 Project
Iperf3 Project iperf3
Vendors & Products Iperf3 Project
Iperf3 Project iperf3
Type Values Removed Values Added
Description 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.
Title Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-20
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 4, 2026, 11:23 PM
Reserved
Aug 5, 2026, 8:41 AM
Status
Awaiting Analysis
Published
Aug 11, 2026, 9:17 AM
Modified
Nov 5, 2026, 12:17 AM
Severity
Important
Public date
Aug 11, 2026, 8:13 AM