CVE-2026-71217
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.59%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public 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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.59% probability · 46th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:61257
- https://access.redhat.com/errata/RHSA-2026:61389
- https://access.redhat.com/errata/RHSA-2026:61680
- https://access.redhat.com/security/cve/CVE-2026-71217
- https://bugzilla.redhat.com/show_bug.cgi?id=2460984
- https://github.com/esnet/iperf/commit/494dd377eca4689672becdf06a85158557db1586
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.