diff --git a/ext/soap/soap.c b/ext/soap/soap.c
index 6a718f3af14..afd4be8c24c 100644
--- a/ext/soap/soap.c
+++ b/ext/soap/soap.c
@@ -4134,8 +4134,10 @@ static xmlNodePtr serialize_zval(zval *val, sdlParamPtr param, const char *param
 	}
 	xmlParam = master_to_xml(enc, val, style, parent);
 	zval_ptr_dtor(&defval);
-	if (!strcmp((char*)xmlParam->name, "BOGUS")) {
-		xmlNodeSetName(xmlParam, BAD_CAST(paramName));
+	if (xmlParam != NULL) { 
+		if (xmlParam->name == NULL || strcmp((char*)xmlParam->name, "BOGUS") == 0) {
+			xmlNodeSetName(xmlParam, BAD_CAST(paramName));
+		}
 	}
 	return xmlParam;
 }
diff --git a/ext/soap/tests/soap_qname_crash.phpt b/ext/soap/tests/soap_qname_crash.phpt
new file mode 100644
index 00000000000..bcf01d574fa
--- /dev/null
+++ b/ext/soap/tests/soap_qname_crash.phpt
@@ -0,0 +1,48 @@
+--TEST--
+Test SoapClient with excessively large QName prefix in SoapVar
+--EXTENSIONS--
+soap
+--SKIPIF--
+<?php
+if (PHP_INT_SIZE != 8) die("skip: 64-bit only");
+?>
+--INI--
+memory_limit=6144M
+--FILE--
+<?php
+
+class TestSoapClient extends SoapClient {
+    public function __doRequest(
+        $request,
+        $location,
+        $action,
+        $version,
+        $one_way = false,
+    ): ?string {
+        die($request);
+    }
+}
+
+$prefix = str_repeat("A", 2 * 1024 * 1024 * 1024);
+$qname = "{$prefix}:tag";
+
+echo "Attempting to create SoapVar with very large QName\n";
+
+$var = new SoapVar("value", XSD_QNAME, null, null, $qname);
+
+echo "Attempting encoding\n";
+
+$options = [
+    'location' => 'http://127.0.0.1/',
+    'uri' => 'urn:dummy',
+    'trace' => 1,
+    'exceptions' => true,
+];
+$client = new TestSoapClient(null, $options);
+$client->__soapCall("DummyFunction", [$var]);
+?>
+--EXPECT--
+Attempting to create SoapVar with very large QName
+Attempting encoding
+<?xml version="1.0" encoding="UTF-8"?>
+<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="urn:dummy" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><ns1:DummyFunction><param0 xsi:type="xsd:QName">value</param0></ns1:DummyFunction></SOAP-ENV:Body></SOAP-ENV:Envelope>