F5 has published a security advisory detailing a critical vulnerability in its BIG-IP Access Policy Manager (APM) product that is already under active exploitation.
The flaw, identified as CVE-2026-94127, is a heap-based buffer overflow that can be triggered when BIG-IP APM is configured as an OAuth authorization server. Specifically, the vulnerable setup requires a virtual server with both an access policy and an OAuth profile enabled.
Attackers can send specially crafted traffic to achieve arbitrary code execution on the affected system. F5 states that the issue also affects appliance mode deployments.
The vulnerability received a base score of 9.3 on CVSSv4.0 and 9.8 on CVSSv3.1, placing it in the highest severity category of Critical.
F5 discovered the vulnerability internally and has confirmed that it is being exploited in the wild. The company is urging customers to apply available fixes and investigate potential compromises.


