In some circumstances, the Traffic Management Microkernel (TMM) does not properly handle certain malformed Websockets requests/responses, which allows remote attackers to cause a denial-of-service (DoS) or possible remote code execution on the F5 BIG-IP system running versions 13.0.0 - 13.1.0.3 or 12.1.0 - 12.1.3.1.
F5 BIG-IP appliances 9.x before 9.4.8-HF5, 10.x before 10.2.4, 11.0.x before 11.0.0-HF2, and 11.1.x before 11.1.0-HF3, and Enterprise Manager before 2.1.0-HF2, 2.2.x before 2.2.0-HF1, and 2.3.x before 2.3.0-HF3, use a single SSH private key across different customers' installations and do not properly restrict access to this key, which makes it easier for remote attackers to perform SSH logins via the PubkeyAuthentication option.