CISA Adds F5 BIG-IP CVE-2025-53521 to KEV After Exploitation
⚠️ CISA has added CVE-2025-53521 to its Known Exploited Vulnerabilities (KEV) list after evidence of active exploitation against F5 BIG-IP APM. The flaw, reclassified from a DoS to an RCE with a CVSS v4 score of 9.3, permits unauthenticated remote code execution when an APM access policy is configured on a virtual server. F5 published file, log, and traffic indicators and warned that webshells may run in memory. Organizations and FCEB agencies were directed to apply the vendor fixes by March 30, 2026.
