F5 · BIG-IP
CVE-2025-53521
F5 BIG-IP Stack-Based Buffer Overflow Vulnerability
CISA KEV record
- CISA date added
- 2026-03-27
- CISA due date
- 2026-03-30
- Known ransomware use
- Unknown
NVD risk context
9.3 CRITICAL
CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.
Description
F5 BIG-IP APM contains a stack-based buffer overflow vulnerability that could allow a threat actor to achieve remote code execution.
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.
NVD reference index
Vendor and remediation references
NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.
Other NVD references (1)
MITRE CWE context
CWE classification
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
View official MITRE CWE details ↗NVD record timing
NVD record timeline
These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.
- NVD published
- Oct 15, 2025, 02:15 PM UTC When NVD first published this CVE record.
- NVD last updated
- Jun 17, 2026, 09:38 AM UTC When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector
This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.
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
CISA notes
Please adhere to F5’s guidelines to assess exposure and mitigate risks. Check for signs of potential compromise on all internet accessible F5 products affected by this vulnerability. For more information please see: https://my.f5.com/manage/s/article/K000156741 ; https://my.f5.com/manage/s/article/K000160486 ; https://my.f5.com/manage/s/article/K11438344 ; https://nvd.nist.gov/vuln/detail/CVE-2025-53521