CVE-2026-71217

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

HIGH
7.5
CVSS Score
Published: August 11, 2026 at 08:50 AM UTC
Updated: August 31, 2026 at 04:26 PM UTC
1 product affected across 1 vendorEnterprise Linux

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 0:3.17.1-6.el10_2.1 (unaffected)
Vendor states this is fixed in 0:3.5-12.el8_10.1 (unaffected)
Vendor states this is fixed in 0:3.9-17.el9_8.1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61257
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61389
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61680

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-20

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