diff --git a/lib/private/Security/Normalizer/IpAddress.php b/lib/private/Security/Normalizer/IpAddress.php
index 84c87054c7..4edf83eca5 100644
--- a/lib/private/Security/Normalizer/IpAddress.php
+++ b/lib/private/Security/Normalizer/IpAddress.php
@@ -68,6 +68,9 @@ class IpAddress {
 	 * @return string
 	 */
 	private function getIPv6Subnet(string $ip, int $maskBits = 48): string {
+		if ($ip[0] === '[' && $ip[-1] === ']') { // If IP is with brackets, for example [::1]
+			$ip = substr($ip, 1, strlen($ip) - 2);
+		}
 		$binary = \inet_pton($ip);
 		for ($i = 128; $i > $maskBits; $i -= 8) {
 			$j = \intdiv($i, 8) - 1;
diff --git a/tests/lib/Security/Normalizer/IpAddressTest.php b/tests/lib/Security/Normalizer/IpAddressTest.php
index 36a48f601d..97a8737ea9 100644
--- a/tests/lib/Security/Normalizer/IpAddressTest.php
+++ b/tests/lib/Security/Normalizer/IpAddressTest.php
@@ -40,6 +40,10 @@ class IpAddressTest extends TestCase {
 				'2001:0db8:85a3:0000:0000:8a2e:0370:7334',
 				'2001:db8:85a3::8a2e:370:7334/128',
 			],
+			[
+				'[::1]',
+				'::1/128',
+			],
 		];
 	}