diff --git a/markdown/__main__.py b/markdown/__main__.py
index 38d08fe0..43e486c9 100644
--- a/markdown/__main__.py
+++ b/markdown/__main__.py
@@ -26,9 +26,17 @@
 import warnings
 import markdown
 try:
-    import yaml
+    # We use `unsafe_load` because users may need to pass in actual Python
+    # objects. As this is only available from the CLI, the user has much
+    # worse problems if an attacker can use this as an attach vector.
+    from yaml import unsafe_load as yaml_load
 except ImportError:  # pragma: no cover
-    import json as yaml
+    try:
+        # Fall back to PyYAML <5.1
+        from yaml import load as yaml_load
+    except ImportError:
+        # Fall back to JSON
+        from json import load as yaml_load
 
 import logging
 from logging import DEBUG, WARNING, CRITICAL
@@ -97,7 +105,7 @@ def parse_options(args=None, values=None):
             options.configfile, mode="r", encoding=options.encoding
         ) as fp:
             try:
-                extension_configs = yaml.load(fp)
+                extension_configs = yaml_load(fp)
             except Exception as e:
                 message = "Failed parsing extension config file: %s" % \
                           options.configfile
--- a/tests/__init__.py.orig	2018-01-05 01:41:13.000000000 +0100
+++ b/tests/__init__.py	2019-03-22 22:41:00.850729644 +0100
@@ -17,13 +17,16 @@
 except ImportError:
     tidylib = None
 try:
-    import yaml
-except ImportError as e:
-    msg = e.args[0]
-    msg = msg + ". A YAML library is required to run the Python-Markdown " \
-        "tests. Run `pip install pyyaml` to install the latest version."
-    e.args = (msg,) + e.args[1:]
-    raise
+    from yaml import unsafe_load as yaml_load
+except ImportError: # PyYAML < 5.1
+    try:
+        from yaml import load as yaml_load
+    except ImportError as e:
+        msg = e.args[0]
+        msg = msg + ". A YAML library is required to run the Python-Markdown " \
+            "tests. Run `pip install pyyaml` to install the latest version."
+        e.args = (msg,) + e.args[1:]
+        raise
 
 test_dir = os.path.abspath(os.path.dirname(__file__))
 
@@ -36,7 +39,7 @@
         self._config = {}
         if os.path.exists(filename):
             with codecs.open(filename, encoding="utf-8") as f:
-                self._config = yaml.load(f)
+                self._config = yaml_load(f)
 
     def get(self, section, option):
         """ Get config value for given section and option key. """