In F5 BIG-IP AAM and PEM software version 12.0.0 to 12.1.1, 11.6.0 to 11.6.1, 11.4.1 to 11.5.4, a remote attacker may create maliciously crafted HTTP request to cause Traffic Management Microkernel (TMM) to restart and temporarily fail to process traffic. This issue is exposed on virtual servers using a Policy Enforcement profile or a Web Acceleration profile. Systems that do not have BIG-IP AAM module provisioned are not vulnerable. The Traffic Management Microkernel (TMM) may restart and temporarily fail to process traffic. Systems that do not have BIG-IP AAM or PEM module provisioned are not vulnerable.
https://support.f5.com/csp/article/K19430431