diff --git a/CHANGELOG.md b/CHANGELOG.md
index af33efa..c9a02a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,11 +5,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Fixed
+- Fix issue of TypeError: cannot unpack non-iterable PDFObjRef object, when unpacking the value of 'DW2' ([#529](https://github.com/pdfminer/pdfminer.six/pull/529))
+
 ## Removed
 - Support for Python 3.4 and 3.5 ([#522](https://github.com/pdfminer/pdfminer.six/pull/522))
 - Unused dependency on `sortedcontainers` package ([#525](https://github.com/pdfminer/pdfminer.six/pull/525))
 
-
 ## [20201018]
 
 ### Deprecated
diff --git a/pdfminer/pdffont.py b/pdfminer/pdffont.py
index e1f5a5d..c0da1b6 100644
--- a/pdfminer/pdffont.py
+++ b/pdfminer/pdffont.py
@@ -706,7 +706,7 @@ class PDFCIDFont(PDFFont):
             widths = get_widths2(list_value(spec.get('W2', [])))
             self.disps = {cid: (vx, vy)
                           for (cid, (_, (vx, vy))) in widths.items()}
-            (vy, w) = spec.get('DW2', [880, -1000])
+            (vy, w) = resolve1(spec.get('DW2', [880, -1000]))
             self.default_disp = (None, vy)
             widths = {cid: w for (cid, (w, _)) in widths.items()}
             default_width = w