Critical severity · published Sep 30, 2026
CVE-2026-101276
iperf3 3.21 (esnet/iperf) contains a remote, unauthenticated heap use-after-free: the server's per-test watchdog server_timer_proc() frees streams without cancelling/joining their…
9.2
CVSS
0.4%
EPSS
No
On KEV
Description
iperf3 3.21 (esnet/iperf) contains a remote, unauthenticated heap use-after-free: the server's per-test watchdog server_timer_proc() frees streams without cancelling/joining their worker threads, so a blocked worker dereferences a freed iperf_stream; fixed in 3.22.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
IP
iperf3 · esnet
3.21 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-101276
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-101276
release-notes
https://newreleases.io/project/github/esnet/iperf/release/3.22
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