diff --git a/tests/test_main.py b/tests/test_main.py
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -39,10 +39,19 @@ def test_applies_largefiles_patch_only_i
 
 
 @pytest.mark.parametrize('given, expected', [
+    ('bad', 'bad'),
+    ('query&foo=bar', 'query&foo=bar'),
+    ('equery&auth_token=bar', 'equery&auth_token=*****'),
+    ('a;b;c;query&foo=bar&auth_token=secret',
+     'a&b&c&query&foo=bar&auth_token=*****'),
+    ('', ''),
+    (None, None),
     ('foo=bar', 'foo=bar'),
     ('auth_token=secret', 'auth_token=*****'),
-    ('auth_token=secret&api_key=secret2', 'auth_token=*****&api_key=*****'),
-    ('auth_token=secret&api_key=secret2&param=value', 'auth_token=*****&api_key=*****&param=value'),
+    ('auth_token=secret&api_key=secret2',
+     'auth_token=*****&api_key=*****'),
+    ('auth_token=secret&api_key=secret2&param=value',
+     'auth_token=*****&api_key=*****&param=value'),
 ])
 def test_obfuscate_qs(given, expected):
     assert expected == obfuscate_qs(given)
diff --git a/vcsserver/base.py b/vcsserver/base.py
--- a/vcsserver/base.py
+++ b/vcsserver/base.py
@@ -72,10 +72,14 @@ class RepoFactory(object):
 
 
 def obfuscate_qs(query_string):
+    if query_string is None:
+        return None
+
     parsed = []
-    for k, v in urlparse.parse_qsl(query_string):
+    for k, v in urlparse.parse_qsl(query_string, keep_blank_values=True):
         if k in ['auth_token', 'api_key']:
             v = "*****"
         parsed.append((k, v))
 
-    return '&'.join('{}={}'.format(k,v) for k,v in parsed)
+    return '&'.join('{}{}'.format(
+        k, '={}'.format(v) if v else '') for k, v in parsed)