CVE-2026-102253 iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS
Remote attackers can cause a permanent denial of service in iperf3 servers by triggering an infinite loop in the UDP receive worker with crafted packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-102253?
CVE-2026-102253 is a high-severity denial of service vulnerability in esnet iperf3, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-835
Which versions are affected by CVE-2026-102253?
Linux distribution packages (2)
iperf3 AlmaLinux:10 | All versions | 3.17.1-6.el10_2.2 |
iperf3 Rocky Linux:10 | All versions | 0:3.17.1-6.el10_2.2 |
How do I fix CVE-2026-102253?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-102253 being exploited?
There is no known exploitation of CVE-2026-102253 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as ALSA-2026:88207, AZL-105051, BELL-CVE-2026-102253, DEBIAN-CVE-2026-102253, GHSA-jhpr-vprv-wh8f, MINI-r7jc-pp9j-682p and 2 more.