diff --git a/neutron_lib/constants.py b/neutron_lib/constants.py
index b78eaace6..9090abe59 100644
--- a/neutron_lib/constants.py
+++ b/neutron_lib/constants.py
@@ -625,7 +625,7 @@ METADATA_V4_CIDR = '169.254.169.254/32'
 METADATA_V4_SUBNET = '169.254.0.0/16'
 
 METADATA_V6_IP = 'fe80::a9fe:a9fe'
-METADATA_V6_CIDR = 'fe80::a9fe:a9fe/64'
+METADATA_V6_CIDR = 'fe80::a9fe:a9fe/128'
 
 METADATA_PORT = 80