diff --git a/src/libraries/System.Formats.Tar/src/System/Formats/Tar/SubReadStream.cs b/src/libraries/System.Formats.Tar/src/System/Formats/Tar/SubReadStream.cs
index efa933d02fa70b..bf152c53c09def 100644
--- a/src/libraries/System.Formats.Tar/src/System/Formats/Tar/SubReadStream.cs
+++ b/src/libraries/System.Formats.Tar/src/System/Formats/Tar/SubReadStream.cs
@@ -29,7 +29,7 @@ public SubReadStream(Stream superStream, long startPosition, long maxLength)
             }
             _startInSuperStream = startPosition;
             _positionInSuperStream = startPosition;
-            _endInSuperStream = startPosition + maxLength;
+            _endInSuperStream = checked(startPosition + maxLength);
             _superStream = superStream;
             _isDisposed = false;
             _hasReachedEnd = false;
diff --git a/src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs b/src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs
index ea2fc10ec55699..2fa9c22ad70dbe 100644
--- a/src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs
+++ b/src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs
@@ -264,7 +264,7 @@ public SubReadStream(Stream superStream, long startPosition, long maxLength)
         {
             _startInSuperStream = startPosition;
             _positionInSuperStream = startPosition;
-            _endInSuperStream = startPosition + maxLength;
+            _endInSuperStream = checked(startPosition + maxLength);
             _superStream = superStream;
             _canRead = true;
             _isDisposed = false;