HIGH

CVE-2026-71217

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

CVSS v3

7.5

HIGH

EPSS Score

exploit probability

CISA KEV

No

known exploited

Exploitation

SSVC status

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.

Technical details

CVSS v3 Vector
3.1
Published
8/11/2026
Last Modified
8/11/2026

Frequently asked questions

What is CVE-2026-71217?

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.

Is CVE-2026-71217 actively exploited?

Active exploitation of CVE-2026-71217 has not been confirmed. The EPSS score is N/A%, indicating the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-71217?

CVE-2026-71217 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string 3.1.

Is CVE-2026-71217 affecting your environment?

Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.