VulnerabilityALERT Critical

CVE-2025-53521: F5 BIG-IP Stack-Based Buffer Overflow Vulnerability

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

Impact

CISA lists CVE-2025-53521 as known exploited in the wild for F5 BIG-IP. Ransomware campaign use: Unknown. Federal remediation due date: 2026-03-30.

Recommended 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.

Published: 3/27/2026, 12:00:00 AMSource: CISA Known Exploited Vulnerabilities CatalogTags: CVE-2025-53521, F5, BIG-IP, CISA KEV, CWE-121