Vulnerability affecting F5 BIG-IP APM Organisations have been encouraged to take action against a vulnerability affecting F5 BIG-IP Access Policy Manager. The NCSC is encouraging UK organisations to take immediate action to mitigate an unauthenticated remote code execution vulnerability affecting F5 BIG-IP Access Policy Manager (CVE-2025-53521). F5 BIG-IP APM is a common component, especially within large enterprises. F5 has published an updated security advisory explaining that a previously disclosed vulnerability in BIG-IP APM has been recategorised as an unauthenticated remote code execution vulnerability CVE-2025-53521: When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). F5 is aware of active…