Improper isolation of shared resources on System-on-a-chip (SOC) could a privileged attacker to tamper with the contents of the PSP reserved DRAM region potentially resulting in loss of confidentiality and integrity.
https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-6018.html
https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-4012.html