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Public proof of conceptFix availableAwaiting NVD analysis

CVE-2026-71217

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

A public proof of concept exists; no exploitation attested.

  • Published2026-08-11
  • WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-08-1108:50CVE publishedCNA
  2. 2026-08-1109:17CVE publishedNVD

Versions per branch

Products declared by the CNA4 products

As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-04

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • iperfSUSE:Linux Micro Extras 6.2all versions · fixed in 3.21-160000.1.1
  • iperfSUSE:Linux Enterprise Server for SAP applications 16.0all versions · fixed in 3.21-160000.1.1
  • iperfSUSE:Linux Enterprise Server 16.0all versions · fixed in 3.21-160000.1.1
  • iperfSUSE:Linux Enterprise Module for Package Hub 15 SP7all versions · fixed in 3.22-150000.3.18.1
  • iperfSUSE:Enterprise Storage 7.1all versions · fixed in 3.22-150000.3.18.1
  • iperfopenSUSE:Tumbleweedall versions · fixed in 3.22-1.1
  • iperfopenSUSE:Leap 16.0all versions · fixed in 3.21-160000.1.1
  • iperfMageia:10all versions · fixed in 3.22-1.mga10

31 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-71217 Red Hat Product Security45 products fixed · 3 known affected

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

    iperf3 as a component of Red Hat Enterprise Linux 7 · iperf3-devel as a component of Red Hat Enterprise Linux 7 · iperf3.src as a component of Red Hat Enterprise Linux 7

  • RHSA-2026:61680 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: iperf3 security update

  • RHSA-2026:61389 Red Hat Product Security16 products fixed

    Red Hat Security Advisory: iperf3 security update

  • RHSA-2026:61257 Red Hat Product Security16 products fixed

    Red Hat Security Advisory: iperf3 security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:61680 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Workaround from the vendor Red Hat Product Security RHSA-2026:61680 · 13 productsTo 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.
  3. No fix available, says the vendor Red Hat Product Security CVE-2026-71217 · 3 productsAffected

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-08-11
Last Modified
2026-11-05
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-4jvc-h3x3-w6qj

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. Its EPSS score was 0.6% on 2026-11-09, 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 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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