CVE-2026-71217

A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as parallel and len, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server.

Iperf is a tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to timing, protocols, and buffers.

Security Fix(es):

A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as parallel and len, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server.(CVE-2026-71217)

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as parallel and len, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server.

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Iperf is a tool which can measure maximum TCP bandwidth and tune various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, and data-gram loss.

Security Fix(es):

• iperf3: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (CVE-2026-71217)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as parallel and len, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server.

• CVE-2026-71217: fix missing JSON value range checks in get_parameters() that allowed out-of-range and invalid test parameters from the client

• CVE-2026-71217: add JSON value checks for get_parameters to prevent resource exhaustion from oversized control-channel parameters

Iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion. (CVE-2026-71217) Unbounded peer-controlled allocation in iperf3 json_read() allows unauthenticated remote memory exhaustion. (CVE-2026-71218) 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. (CVE-2026-101276) Iperf3 3.20–3.21 (esnet/iperf) has a pre-auth heap buffer overflow in decrypt_rsa_message(): a 256-byte RSA buffer is BIO_read with the attacker-controlled ciphertext length (guard warns only), so an unauthenticated client overflows the heap via an oversized authtoken. (CVE-2026-101283) Iperf3 < 3.22 UDP Receive Worker Infinite Loop DoS. (CVE-2026-102253)

These are all security issues fixed in the iperf-3.22-1.1 package on the GA media of openSUSE Tumbleweed.

This update for iperf fixes the following issues:

• CVE-2026-71217: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (bsc#1284405).
• CVE-2026-71218: unbounded peer-controlled allocation in JSON_read() allows unauthenticated remote memory exhaustion (bsc#1284404).
• 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 worker threads (bsc#1283786).
• CVE-2026-101283: iperf3 3.20--3.21 (esnet/iperf) has a pre-auth heap buffer overflow in decrypt_rsa_message(): a 256-byte RSA buffer is BIO_read with the attacker-controlled ciphertext length (bsc#1283787).
• CVE-2026-102253: missing checks in the server's UDP receive worker allows unauthenticated remote attackers to cause an infinite loop (bsc#1283528).

Changes for iperf:

• Updated to version 3.22

This update for iperf fixes the following issues:

• CVE-2026-71217: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (bsc#1284405).
• CVE-2026-71218: unbounded peer-controlled allocation in JSON_read() allows unauthenticated remote memory exhaustion (bsc#1284404).
• 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 worker threads (bsc#1283786).
• CVE-2026-101283: iperf3 3.20--3.21 (esnet/iperf) has a pre-auth heap buffer overflow in decrypt_rsa_message(): a 256-byte RSA buffer is BIO_read with the attacker-controlled ciphertext length (bsc#1283787).
• CVE-2026-102253: missing checks in the server's UDP receive worker allows unauthenticated remote attackers to cause an infinite loop (bsc#1283528).

Changes for iperf:

• Updated to version 3.22

This update for iperf fixes the following issues:

• CVE-2026-71217: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (bsc#1284405).
• CVE-2026-71218: unbounded peer-controlled allocation in JSON_read() allows unauthenticated remote memory exhaustion (bsc#1284404).
• 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 worker threads (bsc#1283786).
• CVE-2026-101283: iperf3 3.20--3.21 (esnet/iperf) has a pre-auth heap buffer overflow in decrypt_rsa_message(): a 256-byte RSA buffer is BIO_read with the attacker-controlled ciphertext length (bsc#1283787).
• CVE-2026-102253: missing checks in the server's UDP receive worker allows unauthenticated remote attackers to cause an infinite loop (bsc#1283528).

Changes for iperf:

• Updated to version 3.22

This update for iperf fixes the following issues:

• CVE-2026-71217: iperf3 server accepts unbounded peer-controlled JSON parameters enabling remote denial of service via resource exhaustion (bsc#1284405).
• CVE-2026-71218: unbounded peer-controlled allocation in JSON_read() allows unauthenticated remote memory exhaustion (bsc#1284404).
• 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 worker threads (bsc#1283786).
• CVE-2026-101283: iperf3 3.20--3.21 (esnet/iperf) has a pre-auth heap buffer overflow in decrypt_rsa_message(): a 256-byte RSA buffer is BIO_read with the attacker-controlled ciphertext length (bsc#1283787).
• CVE-2026-102253: missing checks in the server's UDP receive worker allows unauthenticated remote attackers to cause an infinite loop (bsc#1283528).

Changes for iperf:

• Updated to version 3.22.