diff --git a/libs/libvpx/vp9/encoder/vp9_subexp.c b/libs/libvpx/vp9/encoder/vp9_subexp.c
index 04a5dc8936..e7db5f4ce4 100644
--- a/libs/libvpx/vp9/encoder/vp9_subexp.c
+++ b/libs/libvpx/vp9/encoder/vp9_subexp.c
@@ -75,7 +75,7 @@ static int remap_prob(int v, int m) {
     i = recenter_nonneg(MAX_PROB - 1 - v, MAX_PROB - 1 - m) - 1;
 
   assert(i >= 0 && (size_t)i < sizeof(map_table));
-  i = map_table[i];
+  if (i >= 0 && (size_t)i < sizeof(map_table)) i = map_table[i];
   return i;
 }