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.
| Vendor | F5 |
|---|---|
| Product | BIG-IP |
| Date added to KEV | 2026-03-27 |
| Due date (BOD 22-01) | 2026-03-30 |
| Known ransomware campaign use | Unknown |
| CWE | CWE-121 |
| 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. |
What to do
- Identify every instance of F5 BIG-IP in your environment (asset inventory, EDR, vulnerability scanner).
- Apply CISA's 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.
- Federal civilian agencies must act by 2026-03-30 under BOD 22-01; other organizations can use the same date as a target.
- Check the vendor advisory and NVD entry linked below for affected versions, then record the fix in your change log.
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