diff --git a/src/core/fonts.js b/src/core/fonts.js
index 996dbf98d..246d1d630 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -2396,6 +2396,32 @@ var OpenTypeFileBuilder = (function OpenTypeFileBuilderClosure() {
   return OpenTypeFileBuilder;
 })();
 
+// Problematic Unicode characters in the fonts that needs to be moved to avoid
+// issues when they are painted on the canvas, e.g. complex-script shaping or
+// control/whitespace characters. The ranges are listed in pairs: the first item
+// is a code of the first problematic code, the second one is the next
+// non-problematic code. The ranges must be in sorted order.
+var ProblematicCharRanges = new Int32Array([
+  // Control characters.
+  0x0000, 0x0020,
+  0x007F, 0x00A1,
+  0x00AD, 0x00AE,
+  // Chars that is used in complex-script shaping.
+  0x0600, 0x0780,
+  0x08A0, 0x10A0,
+  0x1780, 0x1800,
+  // General punctuation chars.
+  0x2000, 0x2010,
+  0x2011, 0x2012,
+  0x2028, 0x2030,
+  0x205F, 0x2070,
+  0x25CC, 0x25CD,
+  // Chars that is used in complex-script shaping.
+  0xAA60, 0xAA80,
+  // Specials Unicode block.
+  0xFFF0, 0x10000
+]);
+
 /**
  * 'Font' is the class the outside world should use, it encapsulate all the font
  * decoding logics whatever type it is (assuming the font type is supported).
@@ -2679,33 +2705,18 @@ var Font = (function FontClosure() {
    * @return {boolean}
    */
   function isProblematicUnicodeLocation(code) {
-    if (code <= 0x1F) { // Control chars
-      return true;
+    // Using binary search to find a range start.
+    var i = 0, j = ProblematicCharRanges.length - 1;
+    while (i < j) {
+      var c = (i + j + 1) >> 1;
+      if (code < ProblematicCharRanges[c]) {
+        j = c - 1;
+      } else {
+        i = c;
+      }
     }
-    if (code >= 0x80 && code <= 0x9F) { // Control chars
-      return true;
-    }
-    if ((code >= 0x2000 && code <= 0x200F) || // General punctuation chars
-        (code >= 0x2028 && code <= 0x202F) ||
-        (code >= 0x2060 && code <= 0x206F)) {
-      return true;
-    }
-    if (code >= 0xFFF0 && code <= 0xFFFF) { // Specials Unicode block
-      return true;
-    }
-    switch (code) {
-      case 0x7F: // Control char
-      case 0xA0: // Non breaking space
-      case 0xAD: // Soft hyphen
-      case 0x2011: // Non breaking hyphen
-      case 0x205F: // Medium mathematical space
-      case 0x25CC: // Dotted circle (combining mark)
-        return true;
-    }
-    if ((code & ~0xFF) === 0x0E00) { // Thai/Lao chars (with combining mark)
-      return true;
-    }
-    return false;
+    // Even index means code in problematic range.
+    return !(i & 1);
   }
 
   /**
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 70e09390b..ca614c71c 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -130,6 +130,7 @@
 !issue4800.pdf
 !issue4801.pdf
 !issue5334.pdf
+!issue5540.pdf
 !issue5549.pdf
 !issue5475.pdf
 !annotation-border-styles.pdf
diff --git a/test/pdfs/issue5540.pdf b/test/pdfs/issue5540.pdf
new file mode 100644
index 000000000..3c62879a7
Binary files /dev/null and b/test/pdfs/issue5540.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index f6137dc61..855d03273 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1549,6 +1549,12 @@
       "rounds": 1,
       "type": "load"
     },
+    {  "id": "issue5540",
+      "file": "pdfs/issue5540.pdf",
+      "md5": "12b69b19e366232422812ad8b2534f37",
+      "rounds": 1,
+      "type": "eq"
+    },
     {  "id": "issue2176",
       "file": "pdfs/issue2176.pdf",
       "md5": "ca5cbbc7e2b717997f0b24ffa485eac6",