diff --git a/ext/sockets/socket_addrinfo_lookup.php b/ext/sockets/socket_addrinfo_lookup.php
index b46add4f2b5..3142181a578 100644
--- a/ext/sockets/socket_addrinfo_lookup.php
+++ b/ext/sockets/socket_addrinfo_lookup.php
@@ -44,7 +44,9 @@ public function execute(Frame $frame): void
             throw new \LogicException('socket_addrinfo_lookup() requires VM context');
         }
 
-        $host = VmString::coerceTypedStringBuiltinArg($frame->calledArgs[0], 'socket_addrinfo_lookup', 0, 'host');
+        // Z_PARAM_STR — soft-null outside strict_types; strict → TypeError (#30337).
+        // userArgIndex is 0-based for Argument/parameter #N messages (same as socket_connect).
+        $host = VmString::stringBuiltinArgForFrame($frame, 0, 'socket_addrinfo_lookup', 0, 'host', false);
         $service = null;
         if ($argc >= 2) {
             $service = VmString::coerceNullableStringBuiltinArg(
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 4a23f24e78a..2fc8eaed8fb 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -211,6 +211,7 @@
             <file>./test/compliance/SocketErrorNullOptionalVMTest.php</file>
             <file>./test/compliance/SocketBindSoftNullVMTest.php</file>
             <file>./test/compliance/SocketConnectSoftNullVMTest.php</file>
+            <file>./test/compliance/SocketAddrinfoLookupSoftNullVMTest.php</file>
             <file>./test/compliance/SocketSendtoSoftNullVMTest.php</file>
             <file>./test/compliance/SocketWriteSoftNullVMTest.php</file>
             <file>./test/compliance/SocketSendSoftNullVMTest.php</file>
diff --git a/test/compliance/SocketAddrinfoLookupSoftNullVMTest.php b/test/compliance/SocketAddrinfoLookupSoftNullVMTest.php
new file mode 100644
index 00000000000..4074454b6ca
--- /dev/null
+++ b/test/compliance/SocketAddrinfoLookupSoftNullVMTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler;
+
+require_once __DIR__.'/../BaseTest.php';
+
+/** VM: socket_addrinfo_lookup(null) soft-null + strict $host (#30337). */
+final class SocketAddrinfoLookupSoftNullVMTest extends BaseTest
+{
+    protected static string $DIR = __DIR__;
+
+    public static function providePHPTests(): \Generator
+    {
+        yield 'socket_addrinfo_lookup_soft_null.phpt' => self::parsePHPT(
+            __DIR__.'/cases/sockets/socket_addrinfo_lookup_soft_null.phpt',
+            'socket_addrinfo_lookup_soft_null.phpt'
+        );
+        yield 'socket_addrinfo_lookup_null_strict.phpt' => self::parsePHPT(
+            __DIR__.'/cases/sockets/socket_addrinfo_lookup_null_strict.phpt',
+            'socket_addrinfo_lookup_null_strict.phpt'
+        );
+    }
+
+    public function setUp(): void
+    {
+        $this->BIN = realpath(__DIR__.'/../../bin/vm.php');
+    }
+}
diff --git a/test/compliance/cases/sockets/socket_addrinfo_lookup_null_strict.phpt b/test/compliance/cases/sockets/socket_addrinfo_lookup_null_strict.phpt
new file mode 100644
index 00000000000..5c72491e255
--- /dev/null
+++ b/test/compliance/cases/sockets/socket_addrinfo_lookup_null_strict.phpt
@@ -0,0 +1,14 @@
+--TEST--
+stdlib socket_addrinfo_lookup(null) TypeError under strict_types (#30337, ext/sockets/sockets.c)
+--FILE--
+<?php
+declare(strict_types=1);
+error_reporting(E_ALL);
+try {
+    var_export(socket_addrinfo_lookup(null));
+    echo "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ':', $e->getMessage(), "\n";
+}
+--EXPECT--
+TypeError:socket_addrinfo_lookup(): Argument #1 ($host) must be of type string, null given
diff --git a/test/compliance/cases/sockets/socket_addrinfo_lookup_soft_null.phpt b/test/compliance/cases/sockets/socket_addrinfo_lookup_soft_null.phpt
new file mode 100644
index 00000000000..0b3f9e4c43f
--- /dev/null
+++ b/test/compliance/cases/sockets/socket_addrinfo_lookup_soft_null.phpt
@@ -0,0 +1,14 @@
+--TEST--
+stdlib socket_addrinfo_lookup(null) soft-null Deprecated+false (#30337, ext/sockets/sockets.c)
+--FILE--
+<?php
+error_reporting(E_ALL);
+try {
+    var_export(socket_addrinfo_lookup(null));
+    echo "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ':', $e->getMessage(), "\n";
+}
+--EXPECTF--
+PHP Deprecated:  socket_addrinfo_lookup(): Passing null to parameter #1 ($host) of type string is deprecated in %s on line %d
+false
diff --git a/test/repro/issue_30337_socket_addrinfo_lookup_soft_null.php b/test/repro/issue_30337_socket_addrinfo_lookup_soft_null.php
new file mode 100644
index 00000000000..53701f2da8c
--- /dev/null
+++ b/test/repro/issue_30337_socket_addrinfo_lookup_soft_null.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * Repro #30337 — socket_addrinfo_lookup(null) soft-null: Deprecated + false.
+ * php-src: ext/sockets/sockets.c PHP_FUNCTION(socket_addrinfo_lookup)
+ */
+error_reporting(E_ALL);
+try {
+    var_export(socket_addrinfo_lookup(null));
+    echo "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ': ', $e->getMessage(), "\n";
+}