# CVE-2026-102253: iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS

CVE-2026-102253 is fixed in 5 products on 1 platform, first by FEDORA-2026-AF72C5C990, released October 4, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-102253
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 29, 2026
- Weakness: Loop with Unreachable Exit Condition ('Infinite Loop')
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102253

## Description

iperf3 versions prior to 3.22 contains a denial of service vulnerability that allows unauthenticated remote attackers to crash-loop the server's UDP receive worker into an unrecoverable infinite loop by sending a single crafted control-channel parameter message followed by one 16-byte UDP datagram. Attackers can permanently pin the affected per-stream receive thread at approximately 100% CPU usage, rendering the server unusable until forcibly killed with SIGKILL, as the process does not respond to normal control-channel closure.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | iperf opensuse-leap 16.0 | 3.21-160000.1.1 | [OPENSUSE-SU-2026:22090-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22090-1.md) | Nov 7, 2026 |
| Linux | iperf sles 15.7 | 3.22-150000.3.18.1 | [SUSE-SU-2026:4678-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4678-1.md) | Nov 7, 2026 |
| Linux | iperf sles 16.0 | 3.21-160000.1.1 | [SUSE-SU-2026:24234-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24234-1.md) | Nov 7, 2026 |
| Linux | iperf3 Debian 14 | 3.22-0.1 | [DEBIAN-CVE-2026-102253](https://patchblox.com/security/data/fix/linux/debian-cve-2026-102253.md) | Oct 5, 2026 |
| Linux | iperf3 Fedora 43 | 3.22-2.fc43 | [FEDORA-2026-AF72C5C990](https://patchblox.com/security/data/fix/linux/fedora-2026-af72c5c990.md) | Oct 4, 2026 |
| Linux | iperf3 RHEL 10 | 3.17.1-6.el10_2.2 | [RHSA-2026:88207](https://patchblox.com/security/data/fix/linux/rhsa-2026-88207.md) | Oct 24, 2026 |
| Linux | iperf3 almalinux 10 | 3.17.1-6.el10_2.2 | [ALSA-2026:88207](https://patchblox.com/security/data/fix/linux/alsa-2026-88207.md) | Nov 7, 2026 |
| Linux | iperf3 ol 10 | 0:3.17.1-6.el10_2.2 | [ELSA-2026-88207](https://patchblox.com/security/data/fix/linux/elsa-2026-88207.md) | Nov 7, 2026 |
| Linux | iperf3 rocky 10 | 0:3.17.1-6.el10_2.2 | [RLSA-2026:88207](https://patchblox.com/security/data/fix/linux/rlsa-2026-88207.md) | Nov 7, 2026 |
| Linux | iperf3-debuginfo Fedora 43 | 3.22-2.fc43 | [FEDORA-2026-AF72C5C990](https://patchblox.com/security/data/fix/linux/fedora-2026-af72c5c990.md) | Oct 4, 2026 |
| Linux | iperf3-debugsource Fedora 43 | 3.22-2.fc43 | [FEDORA-2026-AF72C5C990](https://patchblox.com/security/data/fix/linux/fedora-2026-af72c5c990.md) | Oct 4, 2026 |
| Linux | iperf3-devel Fedora 43 | 3.22-2.fc43 | [FEDORA-2026-AF72C5C990](https://patchblox.com/security/data/fix/linux/fedora-2026-af72c5c990.md) | Oct 4, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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