diff --git a/cmds/idmap2/libidmap2/XmlParser.cpp b/cmds/idmap2/libidmap2/XmlParser.cpp
index 1d78460..7807155 100644
--- a/cmds/idmap2/libidmap2/XmlParser.cpp
+++ b/cmds/idmap2/libidmap2/XmlParser.cpp
@@ -130,11 +130,14 @@
 }
 
 Result<Res_value> XmlParser::Node::GetAttributeValue(const std::string& name) const {
+  String16 name16;
   return FindAttribute(parser_, name, [&](size_t index) -> bool {
-    size_t len;
-    const String16 key16(parser_.getAttributeName(index, &len));
-    std::string key = String8(key16).c_str();
-    return key == name;
+    if (name16.empty()) {
+        name16 = String16(name.c_str(), name.size());
+    }
+    size_t key_len;
+    const auto key16 = parser_.getAttributeName(index, &key_len);
+    return key16 && name16.size() == key_len && name16 == key16;
   });
 }