CVE-2025-53521

2026-05-133 minNCSCcritical

The NCSC has issued an urgent alert regarding CVE-2025-53521, an actively exploited, unauthenticated remote code execution vulnerability in F5 BIG-IP Access Policy Manager (APM). Organizations are strongly advised to investigate for compromise using vendor-provided indicators, apply updates immediately, and potentially rebuild affected systems if evidence of compromise is found.

2026-05-133 minCISAcritical

CISA has added CVE-2025-53521, a Remote Code Execution vulnerability affecting F5 BIG-IP, to its Known Exploited Vulnerabilities (KEV) Catalog due to evidence of active exploitation. All organizations are strongly urged to prioritize timely remediation to reduce exposure to cyberattacks.