Failure to validate the AMD SMM communication buffer may allow an attacker to corrupt the SMRAM potentially leading to arbitrary code execution.
https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-5001
https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-4002
https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-3002