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CVE-2025-53521: F5 BIG-IP Stack-Based Buffer Overflow Vulnerability
F5 BIG-IP · in CISA KEV since 2026-03-27
2026-03-27added to KEV
2026-03-30federal remediation due date
2.30%EPSS exploit probability (30 days) 82.5th percentile
9.3 CRITICALCVSS 4.0
Unknownknown ransomware use
163days from NVD publication to KEV
What it is
F5 BIG-IP APM contains a stack-based buffer overflow vulnerability that could allow a threat actor to achieve remote code execution.
Required action (CISA)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
| CWE | CWE-121 |
|---|---|
| CVSS vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD published | 2025-10-15 (Analyzed) |
Original records: NVD · CISA KEV · JSON: /api/cve/CVE-2025-53521.json · all KEV CVEs
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Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.
Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.