diff --git a/src/waitress/receiver.py b/src/waitress/receiver.py
index 87852808..6289d1a9 100644
--- a/src/waitress/receiver.py
+++ b/src/waitress/receiver.py
@@ -14,6 +14,7 @@
 """Data Chunk Receiver
 """
 
+from waitress.rfc7230 import CHUNK_EXT_RE, ONLY_HEXDIG_RE
 from waitress.utilities import BadRequest, find_double_newline
 
 
@@ -110,6 +111,7 @@ def received(self, s):
                     s = b""
                 else:
                     self.chunk_end = b""
+
                     if pos == 0:
                         # Chop off the terminating CR LF from the chunk
                         s = s[2:]
@@ -140,7 +142,14 @@ def received(self, s):
                         semi = line.find(b";")
 
                         if semi >= 0:
-                            # discard extension info.
+                            extinfo = line[semi:]
+                            valid_ext_info = CHUNK_EXT_RE.match(extinfo)
+
+                            if not valid_ext_info:
+                                self.error = BadRequest("Invalid chunk extension")
+                                self.all_chunks_received = True
+
+                                break
                             line = line[:semi]
                         try:
                             sz = int(line.strip(), 16)  # hexadecimal
diff --git a/tests/test_functional.py b/tests/test_functional.py
index d1366caf..9e33fc0f 100644
--- a/tests/test_functional.py
+++ b/tests/test_functional.py
@@ -364,6 +364,28 @@ def test_broken_chunked_encoding(self):
             self.send_check_error(to_send)
             self.assertRaises(ConnectionClosed, read_http, fp)
 
+    def test_broken_chunked_encoding_invalid_extension(self):
+        control_line = b"20;invalid=\r\n"  # 20 hex = 32 dec
+        s = b"This string has 32 characters.\r\n"
+        to_send = b"GET / HTTP/1.1\r\nTransfer-Encoding: chunked\r\n\r\n"
+        to_send += control_line + s + b"\r\n"
+        self.connect()
+        self.sock.send(to_send)
+        with self.sock.makefile("rb", 0) as fp:
+            line, headers, response_body = read_http(fp)
+            self.assertline(line, "400", "Bad Request", "HTTP/1.1")
+            cl = int(headers["content-length"])
+            self.assertEqual(cl, len(response_body))
+            self.assertIn(b"Invalid chunk extension", response_body)
+            self.assertEqual(
+                sorted(headers.keys()),
+                ["connection", "content-length", "content-type", "date", "server"],
+            )
+            self.assertEqual(headers["content-type"], "text/plain")
+            # connection has been closed
+            self.send_check_error(to_send)
+            self.assertRaises(ConnectionClosed, read_http, fp)
+
     def test_broken_chunked_encoding_missing_chunk_end(self):
         control_line = b"20\r\n"  # 20 hex = 32 dec
         s = b"This string has 32 characters.\r\n"
diff --git a/tests/test_receiver.py b/tests/test_receiver.py
index f55aa68e..a3b6f994 100644
--- a/tests/test_receiver.py
+++ b/tests/test_receiver.py
@@ -1,5 +1,7 @@
 import unittest
 
+import pytest
+
 
 class TestFixedStreamReceiver(unittest.TestCase):
     def _makeOne(self, cl, buf):
@@ -226,6 +228,41 @@ def test_received_multiple_chunks_split(self):
         self.assertEqual(inst.error, None)
 
 
+class TestChunkedReceiverParametrized:
+    def _makeOne(self, buf):
+        from waitress.receiver import ChunkedReceiver
+
+        return ChunkedReceiver(buf)
+
+    @pytest.mark.parametrize(
+        "invalid_extension", [b"\n", b"invalid=", b"\r", b"invalid = true"]
+    )
+    def test_received_invalid_extensions(self, invalid_extension):
+        from waitress.utilities import BadRequest
+
+        buf = DummyBuffer()
+        inst = self._makeOne(buf)
+        data = b"4;" + invalid_extension + b"\r\ntest\r\n"
+        result = inst.received(data)
+        assert result == len(data)
+        assert inst.error.__class__ == BadRequest
+        assert inst.error.body == "Invalid chunk extension"
+
+    @pytest.mark.parametrize(
+        "valid_extension", [b"test", b"valid=true", b"valid=true;other=true"]
+    )
+    def test_received_valid_extensions(self, valid_extension):
+        # While waitress may ignore extensions in Chunked Encoding, we do want
+        # to make sure that we don't fail when we do encounter one that is
+        # valid
+        buf = DummyBuffer()
+        inst = self._makeOne(buf)
+        data = b"4;" + valid_extension + b"\r\ntest\r\n"
+        result = inst.received(data)
+        assert result == len(data)
+        assert inst.error == None
+
+
 class DummyBuffer:
     def __init__(self, data=None):
         if data is None: