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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
esnet iperf3 unaffected
Version Status Constraints
3.21 affected —

No data.

No data.

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Project Subscriptions

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://newreleases.io/project/github/esnet/iperf/release/3.22 cve-icon cve-icon
History

Wed, 30 Sep 2026 23:15:00 +0000

Type Values Removed Values Added
Title Remote unauthenticated heap use‑after‑free in iperf3 3.21

Wed, 30 Sep 2026 21:15:00 +0000

Type Values Removed Values Added
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.
Weaknesses CWE-416
References
Metrics cvssV4_0

{'score': 9.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Anthropic

Published:

Updated: 2026-09-30T21:13:21.540Z

Reserved: 2026-09-28T11:52:18.066Z

Link: CVE-2026-101276

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-30T21:16:54.913

Modified: 2026-10-01T02:17:43.350

Link: CVE-2026-101276

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-30T23:00:17Z

Weaknesses