CVEvulnerability

CVE-2025-53521

9.3 CRITICAL Known exploited Published 2025-10-15 Modified 2026-10-08 Official page ↗

CISA Known Exploited Vulnerability

F5 BIG-IP Stack-Based Buffer Overflow Vulnerability — F5 BIG-IP

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

Added to KEV: 2026-03-27
Remediation due: 2026-03-30
Ransomware use: Unknown
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.
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

Status: Analyzed
Published: 2025-10-15
Last modified: 2026-10-08
Assigner: [email protected]
CVSS 4.0 ([email protected]): 9.3 CRITICAL — 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
CVSS 3.1 ([email protected]): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses: CWE-121

Description

When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected configurations

• f5 big-ip access policy manager (>= 15.1.0 < 15.1.10.8) • f5 big-ip access policy manager (>= 16.1.0 < 16.1.6.1) • f5 big-ip access policy manager (>= 17.1.0 < 17.1.3) • f5 big-ip access policy manager (>= 17.5.0 < 17.5.1.3)

Weakness · CWE (1)

CWE-121 Stack-based Buffer Overflow weakness

References