
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


if (!dupFirstEntry) {
        glyphZeroId = 0;
      }
      
      var newMapping = adjustMapping(charCodeToGlyphId, hasGlyph, glyphZeroId);
      this.toFontChar = newMapping.toFontChar;
      tables.cmap = {
        tag: "cmap",
        data: createCmapTable(newMapping.charCodeToGlyphId, numGlyphsOut),
      };
      if (!tables["OS/2"] || !validateOS2Table(tables["OS/2"], font)) {
        tables["OS/2"] = {
          tag: "OS/2",
          data: createOS2Table(
            properties,
            newMapping.charCodeToGlyphId,
            metricsOverride
          ),
        };
      }
      if (!isTrueType) {
        try {
          
          cffFile = new Stream(tables["CFF "].data);
          var parser = new CFFParser(
            cffFile,
            properties,
            SEAC_ANALYSIS_ENABLED
          );
          cff = parser.parse();