diff --git a/src/util.c b/src/util.c
index 0fc370a..512808b 100644
--- a/src/util.c
+++ b/src/util.c
@@ -2400,6 +2400,12 @@ MOBI_RET mobi_decode_font_resource(unsigned char **decoded_font, size_t *decoded
             return MOBI_DATA_CORRUPT;
         }
     } else {
+        if (*decoded_size < encoded_size) {
+            buffer_free(buf);
+            free(*decoded_font);
+            debug_print("Font size in record (%zu) larger then declared (%zu)\n", encoded_size, *decoded_size);
+            return MOBI_DATA_CORRUPT;
+        }
         memcpy(*decoded_font, encoded_font, encoded_size);
     }