diff --git a/python_multipart/multipart.py b/python_multipart/multipart.py
index ace4a8f..1382f5c 100644
--- a/python_multipart/multipart.py
+++ b/python_multipart/multipart.py
@@ -1102,10 +1102,17 @@ def data_callback(name: CallbackName, end_i: int, remaining: bool = False) -> No
             c = data[i]
 
             if state == MultipartState.START:
+                # Stop parsing if there is no boundary within the first chunk
+                if i == 16:
+                    msg = "Too much junk in front of first boundary (%d)" % (i,)
+                    self.logger.warning(msg)
+                    e = MultipartParseError(msg)
+                    e.offset = i
+                    raise e
+
                 # Skip leading newlines
                 if c == CR or c == LF:
                     i += 1
-                    self.logger.debug("Skipping leading CR/LF at %d", i)
                     continue
 
                 # index is used as in index into our boundary.  Set to 0.
@@ -1398,9 +1405,9 @@ def data_callback(name: CallbackName, end_i: int, remaining: bool = False) -> No
                     i -= 1
 
             elif state == MultipartState.END:
-                # Do nothing and just consume a byte in the end state.
-                if c not in (CR, LF):
-                    self.logger.warning("Consuming a byte '0x%x' in the end state", c)  # pragma: no cover
+                # Skip junk after the last boundary
+                i = length
+                break
 
             else:  # pragma: no cover (error case)
                 # We got into a strange state somehow!  Just stop processing.