CVE-2026-101276

iperf3 3.21 (esnet/iperf) contains a remote, unauthenticated heap use-after-free: the server's…

Risk score: 67/100
CVSS: 9.2 v4.0
Exploit chance (30 days): 0.4%
Published: 30 Sep 2026

Open in the live forecast Today's forecast

What to know

What it is: 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.
Affected: See advisory
Fix: Upgrade the product to 3.22 or later.
Exploitation: No known exploitation

Why it is Amber

CVSS 9.2 critical
Remotely exploitable without logging in

References

https://newreleases.io/project/github/esnet/iperf/release/3.22

Original 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.

Last activity 30 Sep 2026. Patch Forecast updates every hour.