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NVD / CVE Program· CNA redhat

CVE-2026-71217: Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion

Noroxi assessment

Priority: Monitor (action score 30/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.63% (FIRST EPSS); higher than 50.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: azl3 iperf3 3.17.1-4 on Azure Linux 3.0 3.17.1-5.

Low priority for now. Upgrade to azl3 iperf3 3.17.1-4 on Azure Linux 3.0 3.17.1-5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—Proof of concept Fix available
Published
Aug 11, 2026
Updated
Aug 31, 2026
EPSS
0.6% · 50th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-71217

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Enterprise Linux 10

    • 0:3.17.1-6.el10_2.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsaffected

  • Red Hat Red Hat Enterprise Linux 8

    • 0:3.5-12.el8_10.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 9

    • 0:3.9-17.el9_8.1 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10iperf3before 3.17.1-6.el10_2.13.17.1-6.el10_2.1
AlmaLinux:8iperf3before 3.5-12.el8_10.13.5-12.el8_10.1
AlmaLinux:9iperf3before 3.9-17.el9_8.13.9-17.el9_8.1
Debian:12iperf3from 0—
Debian:14iperf3before 3.22-0.13.22-0.1
openSUSE:Leap 16.0iperfbefore 3.21-160000.1.13.21-160000.1.1
openSUSE:Tumbleweediperfbefore 3.22-1.13.22-1.1
Red Hat:enterprise_linux:10.2iperf3before 0:3.17.1-6.el10_2.10:3.17.1-6.el10_2.1
Red Hat:enterprise_linux:10.2iperf3-debuginfobefore 0:3.17.1-6.el10_2.10:3.17.1-6.el10_2.1
Red Hat:enterprise_linux:10.2iperf3-debugsourcebefore 0:3.17.1-6.el10_2.10:3.17.1-6.el10_2.1
Red Hat:enterprise_linux:8::appstreamiperf3before 0:3.5-12.el8_10.10:3.5-12.el8_10.1
Red Hat:enterprise_linux:8::appstreamiperf3-debuginfobefore 0:3.5-12.el8_10.10:3.5-12.el8_10.1
Red Hat:enterprise_linux:8::appstreamiperf3-debugsourcebefore 0:3.5-12.el8_10.10:3.5-12.el8_10.1
Red Hat:enterprise_linux:9::appstreamiperf3before 0:3.9-17.el9_8.10:3.9-17.el9_8.1
Red Hat:enterprise_linux:9::appstreamiperf3-debuginfobefore 0:3.9-17.el9_8.10:3.9-17.el9_8.1
Red Hat:enterprise_linux:9::appstreamiperf3-debugsourcebefore 0:3.9-17.el9_8.10:3.9-17.el9_8.1
Rocky Linux:10iperf3before 0:3.17.1-6.el10_2.10:3.17.1-6.el10_2.1
Rocky Linux:8iperf3before 0:3.5-12.el8_10.10:3.5-12.el8_10.1
Rocky Linux:9iperf3before 0:3.9-17.el9_8.10:3.9-17.el9_8.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7iperfbefore 3.22-150000.3.18.13.22-150000.3.18.1
SUSE:Linux Micro Extras 6.2iperfbefore 3.21-160000.1.13.21-160000.1.1

Same product

red hat: all records

Other highest-scoring records for the same primary product.

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  • CVE-2026-76578Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials via the self-managed-token aci
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-63623Aug 10, 2026 · Libvirt: information disclosure via world-readable storage volume images during clone/convert
    22Monitor
  • ← EarlierCVE-2026-6426Aug 10, 2026 · Qemu-kvm: vhost inflight migration vmstate integer type mismatch causes out-of-bounds access
    17Monitor
  • Later →CVE-2026-71218Aug 11, 2026 · Iperf3: unbounded peer-controlled allocation in iperf3 json_read() allows unauthenticated remote memory exhaustion
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 iperf3 3.17.1-4 on Azure Linux 3.03.17.1-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:iperf33.5-12.el8_10.1 · AlmaLinux:8Package registry (OSV)
debian:iperf33.22-0.1 · Debian:14Package registry (OSV)
opensuse:iperf3.22-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:iperf30:3.5-12.el8_10.1 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:iperf3-debuginfo0:3.5-12.el8_10.1 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:iperf3-debugsource0:3.5-12.el8_10.1 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:iperf30:3.5-12.el8_10.1 · Rocky Linux:8Package registry (OSV)
suse:iperf3.21-160000.1.1 · SUSE:Linux Micro Extras 6.2Package registry (OSV)
suse:iperf3.22-150000.3.18.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-09-20

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+40 d
  3. TodayOct 31, 2026+82 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-9702748 days apartFlatpak: flatpak: denial of service via unsanitized keys in exported desktop entry / d-bus service files
    14Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records