EXE MIME Type

About Windows executable files

The registered type is application/vnd.microsoft.portable-executable, but servers usually send application/x-msdownload or application/octet-stream. Browsers warn about or block uncommon executables regardless of type; signing them with a code-signing certificate is what builds trust with SmartScreen.

Other types seen for these files: application/x-msdownload , application/x-msdos-program , application/octet-stream . Accept them when reading uploads, but send application/vnd.microsoft.portable-executable yourself.

File signature

EXE files start with 4D 5A ("MZ"). The extension and the type a browser reports for an upload both come from the file name, so check these bytes on the server before trusting a file.

Serve .exe with the right Content-Type

Content-Type: application/vnd.microsoft.portable-executable

application/vnd.microsoft.portable-executable exe dll;

AddType application/vnd.microsoft.portable-executable .exe .dll

@exe path *.exe *.dll
header @exe Content-Type "application/vnd.microsoft.portable-executable"

curl -sI https://example.com/file.exe | grep -i '^content-type'
# Content-Type: application/vnd.microsoft.portable-executable

Set the type in code

res.set('Content-Type', 'application/vnd.microsoft.portable-executable');
// Or make the browser download it:
res.attachment('file.exe');

import mimetypes

mimetypes.add_type('application/vnd.microsoft.portable-executable', '.exe')  # if your system doesn't know it
mimetypes.guess_type('file.exe')[0]  # 'application/vnd.microsoft.portable-executable'

mime.AddExtensionType(".exe", "application/vnd.microsoft.portable-executable")
w.Header().Set("Content-Type", "application/vnd.microsoft.portable-executable")

Accept .exe uploads

<input type="file" accept=".exe,.dll,application/vnd.microsoft.portable-executable">

The accept attribute only filters the file picker; users can still choose another file. Listing the extension as well as the type matters, because operating systems don’t always report the type you expect.

Related types

• .bin (application/octet-stream): Binary data
• .zip (application/zip): ZIP archive
• .apk (application/vnd.android.package-archive): Android package

More programs and binaries

.jar . Look up any extension or type with the MIME type lookup.

Sources

• IANA registration: application/vnd.microsoft.portable-executable
• MDN: Common media types

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Frequently asked questions