Use-After-Free in iperf3 (CVE-2026-101276)
Summary
Vulnerability in iperf3 (CVE-2026-101276). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.22 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-101276 has been found in iperf3.
Risk of unauthorized operations or information disclosure.
What to do: upgrade iperf3 to 3.22 or later.
If unsure, ask your IT team or search "iperf3 CVE-2026-101276" on the vendor's site.
CVE-2026-101276 (iperf3) — CWE-416
Patched: 3.22 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Use-after-free (CWE-416) exists in iperf3.
Check the vendor advisory for the affected versions of iperf3.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 3.22.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'iperf3' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'iperf3' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
iperf3を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade iperf3 to 3.22ステージング環境で 3.22 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web newreleases.io
- web nvd.nist.gov
- web github.com