diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
index f5100fa9ad..7575dbfd0d 100644
--- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
+++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
@@ -367,6 +367,7 @@ WriteToOsS3PerformanceData (
         AsciiSPrint (PerfData->Token, PERF_TOKEN_LENGTH, "0x%11p", Handle);
       } else {
         AsciiStrnCpy (PerfData->Token, Token, PERF_TOKEN_LENGTH);
+        PerfData->Token[PERF_TOKEN_LENGTH] = '\0';
       }
       if (StartTicker == 1) {
         StartTicker = StartValue;