High severity · published Sep 29, 2026
CVE-2026-102253
iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS
7.5
CVSS
0.4%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
IP
iperf3 · esnet
3.14 before 3.22 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102253
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102253
vendor-advisory
https://github.com/esnet/iperf/releases/tag/3.22
release-notes
https://github.com/esnet/iperf/blob/master/RELNOTES.md
third-party-advisory
https://www.vulncheck.com/advisories/iperf3-udp-receive-worker-infinite-loop-dos
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