CVE-2025-53521

F5 BIG-IP

Published 15 Oct 2025 · updated 17 Jun 2026 · Analyzed

9.3 Critical · CVSS 4.0, f5.com

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 27 Mar 2026, with a remediation deadline of 30 Mar 2026 for US federal agencies.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Description

When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

References