F5 security advisory (AV26-949)

F5 BIG-IP Access Policy Manager (APM) contains a heap-based buffer overflow (CWE-122) that is reachable when a virtual server has both an APM access policy and an OAuth profile configured. An unauthenticated remote attacker can send specifically crafted malicious traffic to such a virtual server and achieve remote code execution on the BIG-IP system, which fully compromises the confidentiality, integrity, and availability of the traffic-management device. Systems running in Appliance mode are also vulnerable, and because this is a data plane flaw, the exposure is at the virtual server itself rather than the management control plane. The vulnerability is rated critical (CVSS 4.0: 9.3) with no privileges or user interaction required. No public proof-of-concept or confirmed in-the-wild exploitation is known, and F5 has not evaluated software versions that have reached End of Technical Support.

Do: Inventory virtual servers with an APM access policy plus an OAuth profile and prioritize patching those first, applying the fixed release identified in F5's advisory (EoTS versions must be upgraded to a supported release to receive a fix). Until patched, remove the OAuth profile from internet-facing virtual servers where feasible or restrict access to the virtual server so untrusted sources cannot reach the APM listener. Monitor BIG-IP logs for anomalous traffic to APM-enabled virtual servers, since exploitation would not touch the management plane.