F5 BIG-IP LTM systems 11.x before 11.2.1 HF16, 11.3.x, 11.4.x before 11.4.1 HF11, 11.5.0, 11.5.1 before HF11, 11.5.2, 11.5.3, 11.5.4 before HF2, 11.6.0 before HF8, 11.6.1 before HF1, 12.0.0 before HF4, and 12.1.0 before HF2 allow remote attackers to modify or extract system configuration files via vectors involving NAT64.