CVE-2025-54351 is a high-severity vulnerability affecting iperf3 versions prior to 3.19.1, specifically within the ES vendor project. The vulnerability is classified under CWE-420, which refers to an unprotected alternate channel. The technical root cause is a buffer overflow in the net.c source file when the --skip-rx-copy option is used. This option relates to the handling of MSG_TRUNC in the recv system call, which is used to receive truncated messages. The buffer overflow occurs because the code does not properly validate or limit the data copied when this option is enabled, leading to memory corruption. The CVSS v3.1 score is 8.9 (high), with vector AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L, indicating that the vulnerability can be exploited remotely over the network without privileges or user interaction, but requires high attack complexity. The impact includes complete compromise of confidentiality and integrity, with limited impact on availability. The scope is changed, meaning exploitation can affect components beyond the vulnerable code. No known exploits are currently in the wild, and no patches are linked yet, but the vulnerability is publicly disclosed as of August 3, 2025. iperf3 is a widely used network performance measurement tool, often deployed in enterprise and research environments to test bandwidth and network throughput. The vulnerability could allow attackers to execute arbitrary code or cause memory corruption remotely by sending specially crafted packets to a system running a vulnerable iperf3 server with the --skip-rx-copy option enabled.

For European organizations, the impact of CVE-2025-54351 could be significant, especially in sectors relying on iperf3 for network diagnostics and performance testing, such as telecommunications, research institutions, and large enterprises with complex network infrastructures. Exploitation could lead to unauthorized disclosure of sensitive network performance data, manipulation of test results, or remote code execution, potentially allowing lateral movement within networks or disruption of network monitoring activities. Given the vulnerability requires no authentication or user interaction, attackers could target exposed iperf3 services directly. The high confidentiality and integrity impact could compromise network security postures and trust in network measurements, affecting compliance with data protection regulations like GDPR if sensitive data is leaked. Although availability impact is low, the potential for code execution elevates the risk of broader system compromise. The high attack complexity somewhat limits widespread exploitation but does not eliminate risk to well-resourced attackers or targeted campaigns.

European organizations should immediately audit their environments for iperf3 deployments, particularly versions prior to 3.19.1, and identify any instances where the --skip-rx-copy option is enabled. Until a patch is available, it is critical to disable the --skip-rx-copy option to prevent triggering the vulnerable code path. Network administrators should restrict access to iperf3 services using firewall rules or VPNs to limit exposure to untrusted networks. Monitoring network traffic for unusual or malformed packets targeting iperf3 ports can provide early detection of exploitation attempts. Organizations should also implement network segmentation to isolate performance testing tools from critical infrastructure. Once a patch is released, prompt application of updates is essential. Additionally, consider deploying intrusion detection systems with signatures tuned to detect attempts to exploit this buffer overflow. Conducting regular vulnerability scans and penetration tests focusing on iperf3 can help verify mitigation effectiveness.