patch 9.0.2141: [security]: buffer-overflow in suggest_trie_walk Commit: https://github.com/vim/vim/commit/0fb375aae608d7306b4baf9c1f906961f32e2abf Author: Christian Brabandt <cb@256bit.org> Date: Wed Nov 29 10:23:39 2023 +0100 patch 9.0.2141: [security]: buffer-overflow in suggest_trie_walk Problem: [security]: buffer-overflow in suggest_trie_walk Solution: Check n before using it as index into byts array Basically, n as an index into the byts array, can point to beyond the byts array. So let's double check, that n is within the expected range after incrementing it from sp->ts_curi and bail out if it would be invalid. Reported by @henices, thanks! Signed-off-by: Christian Brabandt <cb@256bit.org>

--- a/src/spellsuggest.c
+++ b/src/spellsuggest.c
@@ -2175,6 +2175,13 @@ suggest_trie_walk(
 	    // - Skip the byte if it's equal to the byte in the word,
 	    //   accepting that byte is always better.
 	    n += sp->ts_curi++;
+
+	    // break out, if we would be accessing byts buffer out of bounds
+	    if (byts == slang->sl_fbyts && n >= slang->sl_fbyts_len)
+	    {
+		got_int = TRUE;
+		break;
+	    }
 	    c = byts[n];
 	    if (soundfold && sp->ts_twordlen == 0 && c == '*')
 		// Inserting a vowel at the start of a word counts less,