diff --git a/src/core/fonts.js b/src/core/fonts.js
index 6d38a0920..a3a52cf62 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -3296,7 +3296,14 @@ var Type1Font = (function Type1FontClosure() {
       var charStringsIndex = new CFFIndex();
       charStringsIndex.add([0x8B, 0x0E]); // .notdef
       for (i = 0; i < count; i++) {
-        charStringsIndex.add(glyphs[i]);
+        var glyph = glyphs[i];
+        // If the CharString outline is empty, replace it with .notdef to
+        // prevent OTS from rejecting the font (fixes bug1252420.pdf).
+        if (glyph.length === 0) {
+          charStringsIndex.add([0x8B, 0x0E]); // .notdef
+          continue;
+        }
+        charStringsIndex.add(glyph);
       }
       cff.charStrings = charStringsIndex;
 
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index c00a37454..cb7707886 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -51,6 +51,7 @@
 !bug1200096.pdf
 !bug1068432.pdf
 !bug1146106.pdf
+!bug1252420.pdf
 !issue5564_reduced.pdf
 !canvas.pdf
 !bug1132849.pdf
diff --git a/test/pdfs/bug1252420.pdf b/test/pdfs/bug1252420.pdf
new file mode 100644
index 000000000..8f01f546e
Binary files /dev/null and b/test/pdfs/bug1252420.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index 785daeefb..f34623bdf 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -776,6 +776,13 @@
        "link": false,
        "type": "load"
     },
+    {  "id": "bug1252420",
+       "file": "pdfs/bug1252420.pdf",
+       "md5": "f21c911b9b655972b06ef782a1fa6a17",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "hudsonsurvey",
        "file": "pdfs/hudsonsurvey.pdf",
        "md5": "bf0e6576a7b6c2fe7485bce1b78e006f",