Media type / application
application/vnd.microsoft.portable-executable
Windows executables and DLLs in the Portable Executable format.
Served inline: Browsers have no renderer for this, so it downloads even without a Content-Disposition header. That makes it the quiet default for anything you do not want opened in place.
Browser behaviour
Downloads
Charset
no charset
Compression
Compress in transit
Send it like this
Content-Type: application/vnd.microsoft.portable-executableA binary payload has no character encoding. A charset parameter here is meaningless and occasionally confuses strict parsers.
Handling verdict
Browsers have no renderer for this, so it downloads even without a Content-Disposition header. That makes it the quiet default for anything you do not want opened in place.
A binary payload has no character encoding. A charset parameter here is meaningless and occasionally confuses strict parsers.
The payload is text-like or otherwise repetitive, so gzip or Brotli removes real bytes. Enable it at the server or CDN.
A `vnd.` subtype belongs to a specific product or organisation. It is registered, but its meaning is defined by that vendor rather than by a standards body.
Anatomy of the name
RFC 6838Top-level type
application
Application
Subtype
vnd.microsoft.portable-executable
Registered in the vendor tree.
Structured syntax
none
No suffix, so the payload format is defined entirely by the subtype itself.
Parameters
none
Beyond the charset rule above, this type defines no parameters of its own.
What trips people up
1 note- The MZ signature at offset 0 is the reliable check; the extension is not, and renaming does not change the bytes.
Response headers
Content-Type: application/vnd.microsoft.portable-executable
X-Content-Type-Options: nosniff
Content-Disposition: attachment; filename="example.exe"
Vary: Accept-Encodingnosniff stops the browser second-guessing the type you declared, which is what makes the rest of this reliable. Content-Disposition: attachment names the saved file and removes any doubt about rendering.
Server configuration
extension mappingnginx
types {
application/vnd.microsoft.portable-executable exe dll;
}Apache
AddType application/vnd.microsoft.portable-executable .exe .dllCaddy
@type path *.exe *.dll
header @type Content-Type "application/vnd.microsoft.portable-executable"Extensions and other spellings
with signatureFile extensions
Also written as
These reach the same handler in practice. Accept them on input; send application/vnd.microsoft.portable-executable on output.
File signature
4D 5A
Check these bytes rather than the client-supplied Content-Type when validating an upload. The header is a claim; the signature is evidence.