diff --git a/poppler/Annot.cc b/poppler/Annot.cc
index 8b5d630..478217f 100644
--- a/poppler/Annot.cc
+++ b/poppler/Annot.cc
@@ -4539,6 +4539,13 @@ void AnnotWidget::drawListBox(FormFieldChoice *fieldChoice,
     wMax = 0;
     for (i = 0; i < fieldChoice->getNumChoices(); ++i) {
       j = 0;
+      if (fieldChoice->getChoice(i) == NULL) {
+        error(errSyntaxError, -1, "Invalid annotation listbox");
+        if (daToks) {
+          deleteGooList(daToks, GooString);
+        }
+        return;
+      }
       layoutText(fieldChoice->getChoice(i), convertedText, &j, font, &w, 0.0, NULL, gFalse);
       if (w > wMax) {
         wMax = w;