diff -ruwbBd libmatroska-1.5.0/src/KaxBlock.cpp libmatroska-1.5.1/src/KaxBlock.cpp
--- libmatroska-1.5.0/src/KaxBlock.cpp	2019-03-12 20:54:34.000000000 +0100
+++ libmatroska-1.5.1/src/KaxBlock.cpp	2019-05-25 12:16:54.000000000 +0200
@@ -628,11 +628,12 @@
       // put all Frames in the list
       if (mLacing != LACING_NONE) {
         // read the number of frames in the lace
-        uint32 LastBufferSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
+        const uint32 TotalLacedSize = GetSize() - BlockHeadSize - 1; // 1 for number of frame
+        uint32 LastBufferSize = TotalLacedSize;
         uint8 FrameNum = _TempHead[0]; // number of frames in the lace - 1
         // read the list of frame sizes
         uint8 Index;
-        int32 FrameSize;
+        uint32 FrameSize;
         uint32 SizeRead;
         uint64 SizeUnknown;
 
@@ -646,6 +647,8 @@
               do {
                 Result += input.read(_TempHead, 1);
                 FrameSize += uint8(_TempHead[0]);
+                if (FrameSize > TotalLacedSize)
+                  throw SafeReadIOCallback::EndOfStreamX(0);
                 LastBufferSize--;
 
                 FirstFrameLocation++;
@@ -662,6 +665,8 @@
             cursor = _tmpBuf = new binary[FrameNum*4]; /// \warning assume the mean size will be coded in less than 4 bytes
             Result += input.read(cursor, FrameNum*4);
             FrameSize = ReadCodedSizeValue(cursor, SizeRead, SizeUnknown);
+            if (FrameSize > TotalLacedSize)
+              throw SafeReadIOCallback::EndOfStreamX(0);
             SizeList[0] = FrameSize;
             cursor += SizeRead;
             LastBufferSize -= FrameSize + SizeRead;
@@ -670,6 +675,8 @@
               // get the size of the frame
               SizeRead = LastBufferSize;
               FrameSize += ReadCodedSizeSignedValue(cursor, SizeRead, SizeUnknown);
+              if (FrameSize > TotalLacedSize)
+                throw SafeReadIOCallback::EndOfStreamX(0);
               SizeList[Index] = FrameSize;
               cursor += SizeRead;
               LastBufferSize -= FrameSize + SizeRead;
@@ -703,7 +710,6 @@
   } catch (SafeReadIOCallback::EndOfStreamX &) {
     SetValueIsSet(false);
 
-    std::memset(EbmlBinary::GetBuffer(), 0, GetSize());
     myBuffers.clear();
     SizeList.clear();
     Timecode           = 0;