diff --git a/Misc/NEWS b/Misc/NEWS
index 769b80e..ff6fe06 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and Builtins
 -----------------
 
+- Issue #18552: Check return value of PyArena_AddPyObject() in
+  obj2ast_object().
+
 - Issue #18560: Fix potential NULL pointer dereference in sum().
 
 - Issue #15905: Fix theoretical buffer overflow in handling of sys.argv[0],
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index 2568222..e61aae2 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -834,9 +834,13 @@
 {
     if (obj == Py_None)
         obj = NULL;
-    if (obj)
-        PyArena_AddPyObject(arena, obj);
-    Py_XINCREF(obj);
+    if (obj) {
+        if (PyArena_AddPyObject(arena, obj) < 0) {
+            *out = NULL;
+            return -1;
+        }
+        Py_INCREF(obj);
+    }
     *out = obj;
     return 0;
 }
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index d78657c..7bf2c50 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -688,9 +688,13 @@
 {
     if (obj == Py_None)
         obj = NULL;
-    if (obj)
-        PyArena_AddPyObject(arena, obj);
-    Py_XINCREF(obj);
+    if (obj) {
+        if (PyArena_AddPyObject(arena, obj) < 0) {
+            *out = NULL;
+            return -1;
+        }
+        Py_INCREF(obj);
+    }
     *out = obj;
     return 0;
 }