CVE-2026-102253: Loop with Unreachable Exit Condition ('Infinite Loop') in esnet iperf3
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.
AI Analysis
Technical Summary
CVE-2026-102253 is a denial of service vulnerability in esnet's iperf3 affecting versions >=3.14 and <3.22. An unauthenticated remote attacker can send a crafted control-channel parameter message followed by a 16-byte UDP datagram to trigger an infinite loop in the UDP receive worker thread. This infinite loop pins the thread at full CPU usage and prevents normal shutdown of the process, requiring a SIGKILL to terminate the affected server instance.
Potential Impact
The vulnerability allows unauthenticated remote attackers to cause a denial of service by crashing the UDP receive worker into an unrecoverable infinite loop. This leads to a per-stream receive thread consuming 100% CPU and renders the iperf3 server unusable until forcibly killed. There is no indication of data compromise or privilege escalation, but service availability is severely impacted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a patch is available, consider restricting access to the iperf3 server to trusted networks to reduce exposure to unauthenticated remote attacks.
CVE-2026-102253: Loop with Unreachable Exit Condition ('Infinite Loop') in esnet iperf3
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.
CVSS v4.0
Score 8.7high
Affected software
esnet
iperf3
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-102253 is a denial of service vulnerability in esnet's iperf3 affecting versions >=3.14 and <3.22. An unauthenticated remote attacker can send a crafted control-channel parameter message followed by a 16-byte UDP datagram to trigger an infinite loop in the UDP receive worker thread. This infinite loop pins the thread at full CPU usage and prevents normal shutdown of the process, requiring a SIGKILL to terminate the affected server instance.
Potential Impact
The vulnerability allows unauthenticated remote attackers to cause a denial of service by crashing the UDP receive worker into an unrecoverable infinite loop. This leads to a per-stream receive thread consuming 100% CPU and renders the iperf3 server unusable until forcibly killed. There is no indication of data compromise or privilege escalation, but service availability is severely impacted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a patch is available, consider restricting access to the iperf3 server to trusted networks to reduce exposure to unauthenticated remote attacks.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-28T19:17:36.656Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abc21e0680226ef68400668
Added to database: 09/29/2026, 20:38:56 UTC
Last enriched: 09/29/2026, 20:51:34 UTC
Last updated: 09/30/2026, 03:03:21 UTC
Views: 7
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