CVE-2026-101276: CWE-416 Use after free in esnet iperf3
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.
AI Analysis
Technical Summary
CVE-2026-101276 is a remote, unauthenticated heap use-after-free vulnerability in esnet iperf3 version 3.21. The vulnerability arises because the server's per-test watchdog function server_timer_proc() frees iperf_stream objects without cancelling or joining the associated worker threads. As a result, a blocked worker thread may dereference a freed iperf_stream, causing a use-after-free condition. This vulnerability is fixed in iperf3 version 3.22.
Potential Impact
Successful exploitation can lead to memory corruption, potentially allowing attackers to cause denial of service or execute arbitrary code remotely without authentication. The CVSS 4.0 score is 9.2, indicating critical severity with high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Upgrade iperf3 to version 3.22 or later, where this use-after-free vulnerability is fixed. No other mitigation is indicated or required.
CVE-2026-101276: CWE-416 Use after free in esnet iperf3
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.
CVSS v4.0
Score 9.2critical
Affected software
esnet
iperf3
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-101276 is a remote, unauthenticated heap use-after-free vulnerability in esnet iperf3 version 3.21. The vulnerability arises because the server's per-test watchdog function server_timer_proc() frees iperf_stream objects without cancelling or joining the associated worker threads. As a result, a blocked worker thread may dereference a freed iperf_stream, causing a use-after-free condition. This vulnerability is fixed in iperf3 version 3.22.
Potential Impact
Successful exploitation can lead to memory corruption, potentially allowing attackers to cause denial of service or execute arbitrary code remotely without authentication. The CVSS 4.0 score is 9.2, indicating critical severity with high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Upgrade iperf3 to version 3.22 or later, where this use-after-free vulnerability is fixed. No other mitigation is indicated or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Anthropic
- Date Reserved
- 2026-09-28T11:52:18.066Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abd7cc62a4e24523d9c87a8
Added to database: 09/30/2026, 21:19:02 UTC
Last enriched: 09/30/2026, 21:32:54 UTC
Last updated: 09/30/2026, 22:13:29 UTC
Views: 4
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