diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-03-01-10-15-06.gh-issue-145376.lG5u1a.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-01-10-15-06.gh-issue-145376.lG5u1a.rst
new file mode 100644
index 00000000000000..a5a6908757e458
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-01-10-15-06.gh-issue-145376.lG5u1a.rst
@@ -0,0 +1 @@
+Fix reference leaks in various unusual error scenarios.
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index ff0e2fd2b3569d..50e93c348afed5 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -3538,8 +3538,10 @@ count_nextlong(countobject *lz)
     if (long_cnt == NULL) {
         /* Switch to slow_mode */
         long_cnt = PyLong_FromSsize_t(PY_SSIZE_T_MAX);
-        if (long_cnt == NULL)
+        if (long_cnt == NULL) {
             return NULL;
+        }
+        lz->long_cnt = long_cnt;
     }
     assert(lz->cnt == PY_SSIZE_T_MAX && long_cnt != NULL);
 
diff --git a/Objects/enumobject.c b/Objects/enumobject.c
index 814ce4f919514b..8feb074f66a0cd 100644
--- a/Objects/enumobject.c
+++ b/Objects/enumobject.c
@@ -184,6 +184,7 @@ increment_longindex_lock_held(enumobject *en)
         if (next_index == NULL) {
             return NULL;
         }
+        en->en_longindex = next_index;
     }
     assert(next_index != NULL);
     PyObject *stepped_up = PyNumber_Add(next_index, en->one);
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 4a98c8e54ab03f..527b970af24bb2 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -4270,7 +4270,9 @@ listiter_reduce_general(void *_it, int forward)
     }
     /* empty iterator, create an empty list */
     list = PyList_New(0);
-    if (list == NULL)
+    if (list == NULL) {
+        Py_DECREF(iter);
         return NULL;
+    }
     return Py_BuildValue("N(N)", iter, list);
 }