CVE-2025-54350 is a vulnerability identified in the iperf3 network performance measurement tool, specifically in versions prior to 3.19.1. The issue lies within the iperf_auth.c component, where a Base64Decode assertion failure occurs when the application processes a malformed authentication attempt. This assertion failure causes the application to exit unexpectedly. The vulnerability is classified under CWE-617, which refers to reachable assertions—assertions in the code that can be triggered by external input, potentially leading to denial of service (DoS). The vulnerability does not allow for unauthorized data access or modification but results in a loss of availability due to the application crash. The CVSS v3.1 base score is 3.7, indicating a low severity level. The attack vector is network-based (AV:N), requiring high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The scope remains unchanged (S:U), and the impact is limited to availability (A:L) with no confidentiality or integrity impact. No known exploits are reported in the wild, and no patches or fixes have been linked yet. The vulnerability arises from insufficient input validation or error handling during Base64 decoding of authentication data, which can be triggered remotely by sending malformed authentication requests to the iperf3 service.

For European organizations, the primary impact of CVE-2025-54350 is a potential denial of service condition on systems running vulnerable versions of iperf3. Since iperf3 is widely used for network performance testing and monitoring, especially in IT infrastructure, telecommunications, and research environments, an attacker could disrupt network diagnostics and performance measurements by causing the tool to crash. This disruption could delay troubleshooting and degrade network management efficiency. However, the impact on confidentiality and integrity is negligible, and the vulnerability does not provide a direct vector for data breaches or privilege escalation. Organizations relying heavily on iperf3 for continuous network monitoring or automated testing may experience operational interruptions. The low severity and high attack complexity reduce the likelihood of widespread exploitation, but targeted attacks against critical network infrastructure could still cause localized service interruptions.

To mitigate this vulnerability, European organizations should upgrade iperf3 to version 3.19.1 or later as soon as the patch becomes available. Until then, network administrators should restrict access to iperf3 services to trusted hosts and networks, employing firewall rules or network segmentation to limit exposure to untrusted sources. Implementing strict input validation and monitoring for malformed authentication attempts in network traffic can help detect exploitation attempts. Additionally, organizations should consider deploying intrusion detection/prevention systems (IDS/IPS) with custom signatures to identify and block malformed Base64 authentication payloads targeting iperf3. Regularly auditing and updating network performance tools and their dependencies will reduce the risk of similar vulnerabilities. Finally, maintaining robust incident response plans to quickly address service disruptions caused by such vulnerabilities is advisable.