diff --git a/grub-core/normal/charset.c b/grub-core/normal/charset.c
index 000e687bd..4f6647116 100644
--- a/grub-core/normal/charset.c
+++ b/grub-core/normal/charset.c
@@ -472,6 +472,9 @@ grub_unicode_aglomerate_comb (const grub_uint32_t *in, grub_size_t inlen,
 	  if (!haveout)
 	    continue;
 
+	  if (out->ncomb == GRUB_UNICODE_NCOMB_MAX)
+	    continue;
+
 	  if (comb_type == GRUB_UNICODE_COMB_MC
 	      || comb_type == GRUB_UNICODE_COMB_ME
 	      || comb_type == GRUB_UNICODE_COMB_MN)
diff --git a/include/grub/unicode.h b/include/grub/unicode.h
index 71a4d1a54..9360b0b97 100644
--- a/include/grub/unicode.h
+++ b/include/grub/unicode.h
@@ -147,7 +147,9 @@ struct grub_unicode_glyph
   grub_uint8_t bidi_level:6; /* minimum: 6 */
   enum grub_bidi_type bidi_type:5; /* minimum: :5 */
 
+#define GRUB_UNICODE_NCOMB_MAX ((1 << 8) - 1)
   unsigned ncomb:8;
+
   /* Hint by unicode subsystem how wide this character usually is.
      Real width is determined by font. Set only in UTF-8 stream.  */
   int estimated_width:8;