diff --git a/endpoints/appr/registry.py b/endpoints/appr/registry.py
index c44e30cb7..731ecc8d7 100644
--- a/endpoints/appr/registry.py
+++ b/endpoints/appr/registry.py
@@ -18,6 +18,7 @@ from endpoints.appr import appr_bp, require_app_repo_read, require_app_repo_writ
 from endpoints.appr.decorators import disallow_for_image_repository
 from endpoints.appr.cnr_backend import Package, Channel, Blob
 from endpoints.decorators import anon_allowed, anon_protect
+from util.names import REPOSITORY_NAME_REGEX
 
 
 logger = logging.getLogger(__name__)
@@ -171,6 +172,11 @@ def pull(namespace, package_name, release, media_type):
 @anon_protect
 def push(namespace, package_name):
   reponame = repo_name(namespace, package_name)
+
+  if not REPOSITORY_NAME_REGEX.match(package_name):
+    logger.debug('Found invalid repository name CNR push: %s', reponame)
+    raise InvalidUsage()
+
   values = request.get_json(force=True, silent=True)
   release_version = values['release']
   media_type = values['media_type']