diff --git a/src/core/fonts.js b/src/core/fonts.js
index 9f4b4efd2..93c88263b 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -4227,11 +4227,12 @@ var Font = (function FontClosure() {
               }
             }
             if (!found && properties.glyphNames) {
-              // Try to map using the post table. There are currently no known
-              // pdfs that this fixes.
+              // Try to map using the post table.
               var glyphId = properties.glyphNames.indexOf(glyphName);
               if (glyphId > 0 && hasGlyph(glyphId, -1, -1)) {
                 charCodeToGlyphId[charCode] = glyphId;
+              } else {
+                charCodeToGlyphId[charCode] = 0; // notdef
               }
             }
           }
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index eea4212a7..65961a4e8 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -137,4 +137,5 @@
 !issue5909.pdf
 !issue6010_1.pdf
 !issue6010_2.pdf
+!issue6068.pdf
 !issue6081.pdf
diff --git a/test/pdfs/issue6068.pdf b/test/pdfs/issue6068.pdf
new file mode 100644
index 000000000..242d9a964
Binary files /dev/null and b/test/pdfs/issue6068.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index c01d42717..82327225e 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1151,6 +1151,13 @@
       "rounds": 1,
       "type": "eq"
     },
+    {  "id": "issue6068",
+       "file": "pdfs/issue6068.pdf",
+       "md5": "bbcedb94776b40352729c16940a5b2bd",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "tamreview",
       "file": "pdfs/TAMReview.pdf",
       "md5": "8039aba56790d3597d2bc8c794a51301",