diff --git a/src/core/fonts.js b/src/core/fonts.js
index 241e50daf..2580b18ee 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -3642,6 +3642,22 @@ var Type1Font = (function Type1FontClosure() {
 
     getGlyphMapping: function Type1Font_getGlyphMapping(properties) {
       var charstrings = this.charstrings;
+
+      if (properties.composite) {
+        const charCodeToGlyphId = Object.create(null);
+        // Map CIDs directly to GIDs.
+        for (
+          let glyphId = 0, charstringsLen = charstrings.length;
+          glyphId < charstringsLen;
+          glyphId++
+        ) {
+          const charCode = properties.cMap.charCodeOf(glyphId);
+          // Add 1 because glyph 0 is duplicated.
+          charCodeToGlyphId[charCode] = glyphId + 1;
+        }
+        return charCodeToGlyphId;
+      }
+
       var glyphNames = [".notdef"],
         glyphId;
       for (glyphId = 0; glyphId < charstrings.length; glyphId++) {
diff --git a/src/core/type1_parser.js b/src/core/type1_parser.js
index 76f5c3d2f..60c6b8506 100644
--- a/src/core/type1_parser.js
+++ b/src/core/type1_parser.js
@@ -437,7 +437,7 @@ var Type1Parser = (function Type1ParserClosure() {
         r = ((value + r) * c1 + c2) & ((1 << 16) - 1);
       }
     }
-    return Array.prototype.slice.call(decrypted, discardNumber, j);
+    return decrypted.slice(discardNumber, j);
   }
 
   function isSpecial(c) {
@@ -457,10 +457,14 @@ var Type1Parser = (function Type1ParserClosure() {
     if (encrypted) {
       var data = stream.getBytes();
       var isBinary = !(
-        isHexDigit(data[0]) &&
+        (isHexDigit(data[0]) || isWhiteSpace(data[0])) &&
         isHexDigit(data[1]) &&
         isHexDigit(data[2]) &&
-        isHexDigit(data[3])
+        isHexDigit(data[3]) &&
+        isHexDigit(data[4]) &&
+        isHexDigit(data[5]) &&
+        isHexDigit(data[6]) &&
+        isHexDigit(data[7])
       );
       stream = new Stream(
         isBinary
diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index 93fee9bd1..7cd219fba 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -224,6 +224,15 @@ if (
     Number.isInteger = require("core-js/es/number/is-integer.js");
   })();
 
+  // Provides support for TypedArray.prototype.slice in legacy browsers.
+  // Support: IE
+  (function checkTypedArraySlice() {
+    if (Uint8Array.prototype.slice) {
+      return;
+    }
+    require("core-js/es/typed-array/slice");
+  })();
+
   // Support: IE, Safari<11, Chrome<63
   (function checkPromise() {
     if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("IMAGE_DECODERS")) {
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 648de4c34..a6ef9da6a 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -206,6 +206,7 @@
 !bug1011159.pdf
 !issue5734.pdf
 !issue4875.pdf
+!issue11740_reduced.pdf
 !issue4881.pdf
 !issue5994.pdf
 !issue6151.pdf
diff --git a/test/pdfs/issue11740_reduced.pdf b/test/pdfs/issue11740_reduced.pdf
new file mode 100644
index 000000000..069bf0514
Binary files /dev/null and b/test/pdfs/issue11740_reduced.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index 9429ca6f9..73f94005e 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -904,6 +904,12 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue11740",
+       "file": "pdfs/issue11740_reduced.pdf",
+       "md5": "f3f2957f171af52229c6e749e8a5572b",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue10491",
        "file": "pdfs/issue10491.pdf",
        "md5": "0759ec46739b13bb0b66170a18d33d4f",