Ensure rented arrays are cleared

src/ImageSharp/Formats/Gif/LzwDecoder.cs

@@ -71,6 +71,10 @@ namespace ImageSharp.Formats
             this.prefix = ArrayPool<int>.Shared.Rent(MaxStackSize);
             this.suffix = ArrayPool<int>.Shared.Rent(MaxStackSize);
             this.pixelStack = ArrayPool<int>.Shared.Rent(MaxStackSize + 1);
+
+            Array.Clear(this.prefix, 0, MaxStackSize);
+            Array.Clear(this.suffix, 0, MaxStackSize);
+            Array.Clear(this.pixelStack, 0, MaxStackSize + 1);
         }
 
         /// <summary>

src/ImageSharp/Formats/Gif/LzwEncoder.cs

@@ -200,6 +200,8 @@ namespace ImageSharp.Formats
 
             this.hashTable = ArrayPool<int>.Shared.Rent(HashSize);
             this.codeTable = ArrayPool<int>.Shared.Rent(HashSize);
+            Array.Clear(this.hashTable, 0, HashSize);
+            Array.Clear(this.codeTable, 0, HashSize);
         }
 
         /// <summary>