do not allow reading negative values with getstr()
diff --git a/Lib/test/test_curses.py b/Lib/test/test_curses.py
index e08fe12..ce5f2a5 100644
--- a/Lib/test/test_curses.py
+++ b/Lib/test/test_curses.py
@@ -185,6 +185,9 @@
         if hasattr(curses, 'enclose'):
             stdscr.enclose()
 
+        self.assertRaises(ValueError, stdscr.getstr, -400)
+        self.assertRaises(ValueError, stdscr.getstr, 2, 3, -400)
+
 
     def test_module_funcs(self):
         "Test module-level functions"
diff --git a/Misc/NEWS b/Misc/NEWS
index c25d682..bd6d212 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -29,6 +29,9 @@
 Library
 -------
 
+- In the curses module, raise an error if window.getstr() is passed a negative
+  value.
+
 - Issue #27758: Fix possible integer overflow in the _csv module for large record
   lengths.
 
diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index b914e5f6..d0d7479 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -918,6 +918,10 @@
     case 1:
         if (!PyArg_ParseTuple(args,"i;n", &n))
             return NULL;
+        if (n < 0) {
+            PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
+            return NULL;
+        }
         Py_BEGIN_ALLOW_THREADS
         rtn2 = wgetnstr(self->win,rtn,MIN(n, 1023));
         Py_END_ALLOW_THREADS
@@ -936,6 +940,10 @@
     case 3:
         if (!PyArg_ParseTuple(args,"iii;y,x,n", &y, &x, &n))
             return NULL;
+        if (n < 0) {
+            PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
+            return NULL;
+        }
 #ifdef STRICT_SYSV_CURSES
         Py_BEGIN_ALLOW_THREADS
         rtn2 = wmove(self->win,y,x)==ERR ? ERR :