F5 BIG-IP Stack-Based Buffer Overflow Vulnerability

Summary

F5 BIG-IP APM contains a stack-based buffer overflow vulnerability that could allow a threat actor to achieve remote code execution.

Why it matters

CVE-2025-53521 is listed in CISA's Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. CISA remediation deadline: 2026-03-30. Treat remediation as urgent.

Operator check

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

Sources