1 files changed, 4 insertions, 0 deletions

diff --git a/src/coding.c b/src/coding.c
index 88ff0ca0a83..37a5e886547 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -811,6 +811,10 @@ decode_composition_emacs_mule (coding, src, src_end,
         return 0;
       for (ncomponent = 0; src < src_base + data_len; ncomponent++)
         {
+          /* If it is longer than this, it can't be valid.  */
+          if (ncomponent >= COMPOSITION_DATA_MAX_BUNCH_LENGTH)
+            return 0;
+
           if (ncomponent % 2 && with_rule)
             {
               ONE_MORE_BYTE (gref);