diff --git a/gunicorn/glogging.py b/gunicorn/glogging.py
index 88f0c133..e876aac8 100644
--- a/gunicorn/glogging.py
+++ b/gunicorn/glogging.py
@@ -471,10 +471,7 @@ class Logger(object):
                     if PY3:  # b64decode returns a byte string in Python 3
                         auth = auth.decode('utf-8')
                     auth = auth.split(":", 1)
-                except TypeError as exc:
-                    self.debug("Couldn't get username: %s", exc)
-                    return user
-                except binascii.Error as exc:
+                except (TypeError, binascii.Error, UnicodeDecodeError) as exc:
                     self.debug("Couldn't get username: %s", exc)
                     return user
                 if len(auth) == 2:
diff --git a/tests/test_logger.py b/tests/test_logger.py
index e719ce02..ed23e98d 100644
--- a/tests/test_logger.py
+++ b/tests/test_logger.py
@@ -46,3 +46,22 @@ def test_get_username_from_basic_auth_header():
     logger = Logger(Config())
     atoms = logger.atoms(response, request, environ, datetime.timedelta(seconds=1))
     assert atoms['u'] == 'brk0v'
+
+
+def test_get_username_handles_malformed_basic_auth_header():
+    """Should catch a malformed auth header"""
+    request = SimpleNamespace(headers=())
+    response = SimpleNamespace(
+        status='200', response_length=1024, sent=1024,
+        headers=(('Content-Type', 'text/plain'),),
+    )
+    environ = {
+        'REQUEST_METHOD': 'GET', 'RAW_URI': '/my/path?foo=bar',
+        'PATH_INFO': '/my/path', 'QUERY_STRING': 'foo=bar',
+        'SERVER_PROTOCOL': 'HTTP/1.1',
+        'HTTP_AUTHORIZATION': 'Basic ixsTtkKzIpVTncfQjbBcnoRNoDfbnaXG',
+    }
+    logger = Logger(Config())
+
+    atoms = logger.atoms(response, request, environ, datetime.timedelta(seconds=1))
+    assert atoms['u'] == '-'