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Microsoft Fax Cover Sheet (.cpe)

.cpe file signature | application/octet-stream

Microsoft Fax Cover Sheet

Safe

Magic Bytes

Offset 0
46 41 58 43 4F 56 45 52 2D 56 45 52

Sources: Gary Kessler

Extension

.cpe

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .cpe files in Python

Python 
def is_cpe(file_path: str) -> bool:
    """Check if file is a valid CPE by magic bytes."""
    signature = bytes([0x46, 0x41, 0x58, 0x43, 0x4F, 0x56, 0x45, 0x52, 0x2D, 0x56, 0x45, 0x52])
    with open(file_path, "rb") as f:
        return f.read(12) == signature

How to validate .cpe files in Node.js

Node.js 
function isCPE(buffer: Buffer): boolean {
  const signature = Buffer.from([0x46, 0x41, 0x58, 0x43, 0x4F, 0x56, 0x45, 0x52, 0x2D, 0x56, 0x45, 0x52]);
  return buffer.subarray(0, 12).equals(signature);
}

How to validate .cpe files in Go

Go 
func IsCPE(data []byte) bool {
    signature := []byte{0x46, 0x41, 0x58, 0x43, 0x4F, 0x56, 0x45, 0x52, 0x2D, 0x56, 0x45, 0x52}
    if len(data) < 12 {
        return false
    }
    return bytes.Equal(data[:12], signature)
}

API Endpoint

GET /api/v1/cpe
curl https://filesignature.org/api/v1/cpe

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .cpe file?

A .cpe file is a Microsoft Fax Cover Sheet file. Microsoft Fax Cover Sheet

What are the magic bytes for .cpe files?

The magic bytes for Microsoft Fax Cover Sheet files are 46 41 58 43 4F 56 45 52 2D 56 45 52 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .cpe file?

To validate a .cpe file, read the first bytes of the file and compare them against the known magic bytes (46 41 58 43 4F 56 45 52 2D 56 45 52) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .cpe files?

There is no officially registered MIME type for .cpe files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .cpe files?

Microsoft Fax Cover Sheet (.cpe) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.