The automatic signature update functionality in the (1) Phone Home feature in F5 BIG-IP LTM, AAM, AFM, Analytics, APM, GTM, and Link Controller 11.5.0 through 11.6.0, ASM 10.0.0 through 11.6.0, and PEM 11.3.0 through 11.6.0 and the (2) Call Home feature in ASM 10.0.0 through 11.6.0 and PEM 11.3.0 through 11.6.0 does not properly validate server SSL certificates, which allows remote attackers to conduct man-in-the-middle attacks via a crafted certificate.