Bug 2543638 (CVE-2026-102253)

Summary: CVE-2026-102253 iperf3: iperf3: Denial of Service via UDP receive worker infinite loop
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in iperf3. An unauthenticated remote attacker can exploit this issue by sending a crafted control-channel message followed by a specific User Datagram Protocol (UDP) datagram to the server. This causes the UDP receive processing thread to enter an unrecoverable infinite loop, leading to sustained high CPU utilization and a Denial of Service (DoS) condition.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2544509    
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Description OSIDB Bzimport 2026-09-29 20:36:59 UTC
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.