diff --git a/lib/private/Security/Normalizer/IpAddress.php b/lib/private/Security/Normalizer/IpAddress.php
index f8e55370da713..459f895b3e6bf 100644
--- a/lib/private/Security/Normalizer/IpAddress.php
+++ b/lib/private/Security/Normalizer/IpAddress.php
@@ -46,7 +46,7 @@ public function __construct(
 	}
 
 	/**
-	 * Return the given subnet for an IPv6 address (64 first bits)
+	 * Return the given subnet for an IPv6 address (48 first bits)
 	 */
 	private function getIPv6Subnet(string $ip): string {
 		if ($ip[0] === '[' && $ip[-1] === ']') { // If IP is with brackets, for example [::1]
@@ -58,9 +58,9 @@ private function getIPv6Subnet(string $ip): string {
 		}
 
 		$binary = \inet_pton($ip);
-		$mask = inet_pton('FFFF:FFFF:FFFF:FFFF::');
+		$mask = inet_pton('FFFF:FFFF:FFFF::');
 
-		return inet_ntop($binary & $mask).'/64';
+		return inet_ntop($binary & $mask).'/48';
 	}
 
 	/**
@@ -85,7 +85,7 @@ private function getEmbeddedIpv4(string $ipv6): ?string {
 
 
 	/**
-	 * Gets either the /32 (IPv4) or the /64 (IPv6) subnet of an IP address
+	 * Gets either the /32 (IPv4) or the /48 (IPv6) subnet of an IP address
 	 */
 	public function getSubnet(): string {
 		if (filter_var($this->ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
diff --git a/tests/lib/Security/Normalizer/IpAddressTest.php b/tests/lib/Security/Normalizer/IpAddressTest.php
index bb487659ced39..3df2c130e9c85 100644
--- a/tests/lib/Security/Normalizer/IpAddressTest.php
+++ b/tests/lib/Security/Normalizer/IpAddressTest.php
@@ -51,20 +51,20 @@ public function subnetDataProvider() {
 				'192.168.0.123/32',
 			],
 			[
-				'2001:0db8:85a3:0000:0000:8a2e:0370:7334',
-				'2001:db8:85a3::/64',
+				'2001:0db8:0000:0000:0000:8a2e:0370:7334',
+				'2001:db8::/48',
 			],
 			[
 				'2001:db8:3333:4444:5555:6666:7777:8888',
-				'2001:db8:3333:4444::/64',
+				'2001:db8:3333::/48',
 			],
 			[
 				'::1234:5678',
-				'::/64',
+				'::/48',
 			],
 			[
 				'[::1]',
-				'::/64',
+				'::/48',
 			],
 		];
 	}