diff --git a/MdeModulePkg/Library/DxeCorePerformanceLib/DxeCorePerformanceLib.c b/MdeModulePkg/Library/DxeCorePerformanceLib/DxeCorePerformanceLib.c
index 7ebdb29fea..0eb8e579d7 100644
--- a/MdeModulePkg/Library/DxeCorePerformanceLib/DxeCorePerformanceLib.c
+++ b/MdeModulePkg/Library/DxeCorePerformanceLib/DxeCorePerformanceLib.c
@@ -191,10 +191,10 @@ StartGaugeEx (
   GaugeEntryExArray[Index].Handle = (EFI_PHYSICAL_ADDRESS) (UINTN) Handle;
 
   if (Token != NULL) {
-    AsciiStrCpyS (GaugeEntryExArray[Index].Token, DXE_PERFORMANCE_STRING_SIZE, Token);
+    AsciiStrnCpyS (GaugeEntryExArray[Index].Token, DXE_PERFORMANCE_STRING_SIZE, Token, DXE_PERFORMANCE_STRING_LENGTH);
   }
   if (Module != NULL) {
-    AsciiStrCpyS (GaugeEntryExArray[Index].Module, DXE_PERFORMANCE_STRING_SIZE, Module);
+    AsciiStrnCpyS (GaugeEntryExArray[Index].Module, DXE_PERFORMANCE_STRING_SIZE, Module, DXE_PERFORMANCE_STRING_LENGTH);
   }
 
   GaugeEntryExArray[Index].EndTimeStamp = 0;
diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmPerformance.c b/MdeModulePkg/Library/UefiBootManagerLib/BmPerformance.c
index dd937a7396..7b13ec663c 100644
--- a/MdeModulePkg/Library/UefiBootManagerLib/BmPerformance.c
+++ b/MdeModulePkg/Library/UefiBootManagerLib/BmPerformance.c
@@ -320,7 +320,7 @@ BmWriteBootToOsPerformanceData (
 
       ZeroMem (&mBmPerfData, sizeof (PERF_DATA));
 
-      AsciiStrCpyS (mBmPerfData.Token, PERF_TOKEN_SIZE, Token);
+      AsciiStrnCpyS (mBmPerfData.Token, PERF_TOKEN_SIZE, Token, PERF_TOKEN_LENGTH);
       if (StartTicker == 1) {
         StartTicker = StartValue;
       }