diff --git a/Zend/tests/gh18581.phpt b/Zend/tests/gh18581.phpt
new file mode 100644
index 0000000000000..cc5c0fff02e92
--- /dev/null
+++ b/Zend/tests/gh18581.phpt
@@ -0,0 +1,32 @@
+--TEST--
+GH-18581: Coerce numeric string keys from iterators when argument unpacking
+--FILE--
+<?php
+
+function g() {
+    yield '100' => 'first';
+    yield '101' => 'second';
+    yield '102' => 'third';
+    yield 'named' => 'fourth';
+}
+
+function test($x = null, $y = null, ...$z) {
+    var_dump($x, $y, $z);
+    var_dump($z[0]);
+    var_dump($z['named']);
+}
+
+test(...g());
+
+?>
+--EXPECT--
+string(5) "first"
+string(6) "second"
+array(2) {
+  [0]=>
+  string(5) "third"
+  ["named"]=>
+  string(6) "fourth"
+}
+string(5) "third"
+string(6) "fourth"
diff --git a/Zend/zend_vm_def.h b/Zend/zend_vm_def.h
index c0e05aef470ae..31a81ff7a3ed4 100644
--- a/Zend/zend_vm_def.h
+++ b/Zend/zend_vm_def.h
@@ -5392,6 +5392,11 @@ ZEND_VM_C_LABEL(send_again):
 						}
 
 						name = Z_STR_P(&key);
+
+						zend_ulong tmp;
+						if (ZEND_HANDLE_NUMERIC(name, tmp)) {
+							name = NULL;
+						}
 					}
 				}
 
diff --git a/Zend/zend_vm_execute.h b/Zend/zend_vm_execute.h
index 387a05943dd19..319f79dc083c5 100644
--- a/Zend/zend_vm_execute.h
+++ b/Zend/zend_vm_execute.h
@@ -2518,6 +2518,11 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_SEND_UNPACK_SPEC_HANDLER(ZEND_
 						}
 
 						name = Z_STR_P(&key);
+
+						zend_ulong tmp;
+						if (ZEND_HANDLE_NUMERIC(name, tmp)) {
+							name = NULL;
+						}
 					}
 				}