Quick answers
- Is CVE-2026-102253 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-102253 being exploited in the wild.
- How severe is CVE-2026-102253?
- High severity, with a CVSS score of 7.5, published 29 September 2026.
- Which products and versions are affected?
- ESnet Iperf3 prior to 3.22.
- Is there a fix for CVE-2026-102253?
- A patch was published on 2026-09-29: Version 3.22 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-102253 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-102253?
- Check whether you run ESnet Iperf3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in iperf3's UDP receive worker thread, where a crafted control-channel parameter message followed by a 16-byte UDP datagram triggers an infinite loop. This is a remotely exploitable denial of service requiring no authentication or user interaction. The affected per-stream receive thread pins at approximately 100% CPU usage and does not respond to normal control-channel closure signals, requiring a SIGKILL to terminate the process.
Affected products
- ESnet iperf3 prior to 3.22
Timeline
- 2026-09-29: disclosed
- 2026-09-29: patched: Version 3.22 released