patch 8.1.1824: crash when correctly spelled word is very long commit https://github.com/vim/vim/commit/5bcc5a1ff94bbab1b175e35a72e3df974106b393 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Aug 6 22:48:02 2019 +0200 patch 8.1.1824: crash when correctly spelled word is very long Problem: Crash when correctly spelled word is very long. (Ben Kraft) Solution: Check word length before copying. (closes https://github.com/vim/vim/issues/4778)

--- a/src/spell.c
+++ b/src/spell.c
@@ -2073,6 +2073,8 @@ count_common_word(
 
     if (len == -1)
 	p = word;
+    else if (len >= MAXWLEN)
+	return;
     else
     {
 	vim_strncpy(buf, word, len);