diff --git a/README.md b/README.md
index 5934274..3a14c95 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,10 @@ The log can be viewed via journalctl (or syslog):
 * Added a shutdown event for custom background workers.
 * `Request.query` is None if there is no query string present. Previously, the query string was an empty string in this case. This allows making a distinction between empty and absent query strings.
 
+v0.3.1:
+
+* CGI: Fixed handling of a missing query string.
+
 ### v0.2
 
 * Added `[cgi] bin_root` configuration option for automatically and dynamically mapping all executables in a directory tree to URL entry points.
diff --git a/gmcapsule/__init__.py b/gmcapsule/__init__.py
index 6dd0cb3..4179daa 100644
--- a/gmcapsule/__init__.py
+++ b/gmcapsule/__init__.py
@@ -440,7 +440,7 @@ from .gemini import Server, Cache
 from .markdown import to_gemtext as markdown_to_gemtext
 
 
-__version__ = '0.3.0'
+__version__ = '0.3.1'
 __all__ = [
     'Config', 'Capsule', 'Cache',
     'get_mime_type', 'markdown_to_gemtext'
diff --git a/gmcapsule/modules/90_cgi.py b/gmcapsule/modules/90_cgi.py
index 51d73a2..a533163 100644
--- a/gmcapsule/modules/90_cgi.py
+++ b/gmcapsule/modules/90_cgi.py
@@ -23,13 +23,13 @@ class CgiContext:
 
     def __call__(self, req):
         try:
-            query = urllib.parse.unquote(req.query)
             env_vars = dict(os.environ)
 
             # Standard CGI variables.
             env_vars['GATEWAY_INTERFACE'] = 'CGI/1.1'
             env_vars['REMOTE_ADDR'] = '%s:%d' % req.remote_address
-            env_vars['QUERY_STRING'] = req.query
+            if req.query != None:
+                env_vars['QUERY_STRING'] = req.query
             env_vars['PATH_INFO'] = req.path
             env_vars['SCRIPT_NAME'] = self.base_path
             env_vars['SERVER_SOFTWARE'] = 'GmCapsule/' + gmcapsule.__version__
@@ -37,7 +37,7 @@ class CgiContext:
             env_vars['SERVER_NAME'] = req.hostname
             env_vars['SERVER_PORT'] = str(Capsule.config().port())
             env_vars[req.scheme.upper() + '_URL'] = f"{req.scheme}://{req.hostname}{req.path}" + (
-                '?' + req.query if len(req.query) else '')
+                '?' + req.query if req.query != None else '')
             env_vars[req.scheme.upper() + '_URL_PATH'] = req.path
 
             # TLS client certificate.