CVE-2025-46706 is a vulnerability classified under CWE-770 (Allocation of Resources Without Limits or Throttling) affecting F5 BIG-IP versions 17.1.0 and 16.1.0. The issue arises when an iRule configured on a virtual server uses the HTTP::respond command. This configuration can be exploited by sending specific, undisclosed HTTP requests that cause the BIG-IP system to allocate excessive memory resources without proper limits or throttling mechanisms. The uncontrolled memory consumption can degrade system performance and ultimately lead to denial of service (DoS) conditions, impacting the availability of the services managed by BIG-IP. The vulnerability can be triggered remotely over the network without requiring authentication or user interaction, increasing its risk profile. Although no public exploits are known at this time, the vulnerability’s nature and ease of exploitation make it a significant threat. The vulnerability does not impact confidentiality or integrity but solely affects availability. F5 BIG-IP is widely used in enterprise environments for load balancing, application delivery, and security functions, making this vulnerability critical in environments where uptime and service continuity are essential. The lack of patches or official remediation guidance at the time of publication necessitates proactive mitigation strategies. The CVSS v3.1 score of 7.5 reflects high severity due to network attack vector, low complexity, no privileges required, and no user interaction needed, with impact limited to availability. Organizations should audit their iRule configurations, especially those using HTTP::respond, and monitor memory usage patterns to detect potential exploitation attempts.

For European organizations, the primary impact of CVE-2025-46706 is the potential for denial of service attacks against critical network infrastructure managed by F5 BIG-IP devices. This can disrupt access to web applications, internal services, and cloud resources, leading to operational downtime and potential financial losses. Industries such as finance, telecommunications, healthcare, and government, which heavily rely on BIG-IP for secure and reliable application delivery, are particularly vulnerable. Service outages could also affect compliance with regulatory requirements around availability and incident response. Additionally, prolonged or repeated exploitation attempts could strain IT resources and incident response teams. The vulnerability’s remote exploitability without authentication increases the attack surface, potentially allowing threat actors to target European organizations from anywhere globally. Given the strategic importance of BIG-IP in securing and optimizing network traffic, successful exploitation could undermine trust in organizational IT infrastructure and impact business continuity.

Since no official patches are currently available for CVE-2025-46706, European organizations should implement the following specific mitigations: 1) Review and audit all iRules configured on BIG-IP devices, focusing on those using the HTTP::respond command, to identify and limit exposure to potentially vulnerable configurations. 2) Implement rate limiting and connection throttling at the network perimeter or on the BIG-IP itself to reduce the risk of resource exhaustion from malicious requests. 3) Monitor memory utilization metrics and set up alerts for abnormal spikes that could indicate exploitation attempts. 4) Employ network segmentation and access controls to restrict exposure of BIG-IP management and virtual servers to untrusted networks. 5) Engage with F5 support and subscribe to their security advisories to receive updates on patches or workarounds as they become available. 6) Consider deploying Web Application Firewalls (WAF) or Intrusion Prevention Systems (IPS) capable of detecting and blocking suspicious HTTP traffic patterns targeting iRule vulnerabilities. 7) Prepare incident response plans specifically addressing potential denial of service scenarios involving BIG-IP infrastructure. These targeted actions go beyond generic advice by focusing on configuration hygiene, proactive monitoring, and network-level protections tailored to the nature of this vulnerability.