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CBOR magic bytes (.cbor)

.cbor file signature: D9 D9 F7 | application/cbor

Concise Binary Object Representation (CBOR) is a binary data interchange format standardized and maintained by the IETF. It is used for compact serialization in web services, IoT devices, embedded systems, and applications that exchange structured data. CBOR is generally safe, but as with other serialized formats, malformed or untrusted input can cause parsing errors or resource exhaustion in poorly implemented decoders.

Safe

Magic Bytes

Offset 0
D9 D9 F7

Sources: Apache Tika

Extension

.cbor

MIME Type

application/cbor

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .cbor files in Python

Python 
def is_cbor(file_path: str) -> bool:
    """Check if file is a valid CBOR by magic bytes."""
    signature = bytes([0xD9, 0xD9, 0xF7])
    with open(file_path, "rb") as f:
        return f.read(3) == signature

How to validate .cbor files in Node.js

Node.js 
function isCBOR(buffer: Buffer): boolean {
  const signature = Buffer.from([0xD9, 0xD9, 0xF7]);
  return buffer.subarray(0, 3).equals(signature);
}

How to validate .cbor files in Go

Go 
func IsCBOR(data []byte) bool {
    signature := []byte{0xD9, 0xD9, 0xF7}
    if len(data) < 3 {
        return false
    }
    return bytes.Equal(data[:3], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .cbor file?

A .cbor file is identified by the magic bytes D9 D9 F7 at byte offset 0. Concise Binary Object Representation (CBOR) is a binary data interchange format standardized and maintained by the IETF. It is used for compact serialization in web services, IoT devices, embedded systems, and applications that exchange structured data. CBOR is generally safe, but as with other serialized formats, malformed or untrusted input can cause parsing errors or resource exhaustion in poorly implemented decoders.

What are the magic bytes for .cbor files?

The magic bytes for CBOR (.cbor) files are D9 D9 F7 at byte offset 0. These bytes identify the file format more reliably than the extension alone.

How do I validate a .cbor file?

To validate a .cbor file, read the first bytes of the file and compare them against the known magic bytes (D9 D9 F7) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .cbor files?

The primary MIME type for .cbor files is application/cbor.

Is it safe to open .cbor files?

CBOR (.cbor) 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.