diff --git a/SecurityPkg/Library/DxeRsa2048Sha256GuidedSectionExtractLib/DxeRsa2048Sha256GuidedSectionExtractLib.c b/SecurityPkg/Library/DxeRsa2048Sha256GuidedSectionExtractLib/DxeRsa2048Sha256GuidedSectionExtractLib.c
index 1f7a29904f..5f5d242d6e 100644
--- a/SecurityPkg/Library/DxeRsa2048Sha256GuidedSectionExtractLib/DxeRsa2048Sha256GuidedSectionExtractLib.c
+++ b/SecurityPkg/Library/DxeRsa2048Sha256GuidedSectionExtractLib/DxeRsa2048Sha256GuidedSectionExtractLib.c
@@ -86,7 +86,7 @@ Rsa2048Sha256GuidedSectionGetInfo (
     //
     *SectionAttribute  = ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->Attributes;
     *ScratchBufferSize = 0;
-    *OutputBufferSize  = SECTION2_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset;
+    *OutputBufferSize  = SECTION2_SIZE (InputSection) - sizeof(RSA_2048_SHA_256_SECTION2_HEADER);
   } else {
     //
     // Check whether the input guid section is recognized.
@@ -101,7 +101,7 @@ Rsa2048Sha256GuidedSectionGetInfo (
     //
     *SectionAttribute  = ((EFI_GUID_DEFINED_SECTION *) InputSection)->Attributes;
     *ScratchBufferSize = 0;
-    *OutputBufferSize  = SECTION_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset;
+    *OutputBufferSize  = SECTION_SIZE (InputSection) - sizeof(RSA_2048_SHA_256_SECTION_HEADER);
   }
 
   return EFI_SUCCESS;
diff --git a/SecurityPkg/Library/PeiRsa2048Sha256GuidedSectionExtractLib/PeiRsa2048Sha256GuidedSectionExtractLib.c b/SecurityPkg/Library/PeiRsa2048Sha256GuidedSectionExtractLib/PeiRsa2048Sha256GuidedSectionExtractLib.c
index e2a0fb6708..e448164a5a 100644
--- a/SecurityPkg/Library/PeiRsa2048Sha256GuidedSectionExtractLib/PeiRsa2048Sha256GuidedSectionExtractLib.c
+++ b/SecurityPkg/Library/PeiRsa2048Sha256GuidedSectionExtractLib/PeiRsa2048Sha256GuidedSectionExtractLib.c
@@ -84,7 +84,7 @@ Rsa2048Sha256GuidedSectionGetInfo (
     //
     *SectionAttribute  = ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->Attributes;
     *ScratchBufferSize = 0;
-    *OutputBufferSize  = SECTION2_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset;
+    *OutputBufferSize  = SECTION2_SIZE (InputSection) - sizeof(RSA_2048_SHA_256_SECTION2_HEADER);
   } else {
     //
     // Check whether the input guid section is recognized.
@@ -99,7 +99,7 @@ Rsa2048Sha256GuidedSectionGetInfo (
     //
     *SectionAttribute  = ((EFI_GUID_DEFINED_SECTION *) InputSection)->Attributes;
     *ScratchBufferSize = 0;
-    *OutputBufferSize  = SECTION_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset;
+    *OutputBufferSize  = SECTION_SIZE (InputSection) - sizeof(RSA_2048_SHA_256_SECTION_HEADER);
   }
 
   return EFI_SUCCESS;