func (ctx *cbcAEAD) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) {
	if len(ciphertext) < ctx.authtagBytes {
		return nil, errors.New("square/go-jose: invalid ciphertext (too short)")
	}

	offset := len(ciphertext) - ctx.authtagBytes
	expectedTag := ctx.computeAuthTag(data, nonce, ciphertext[:offset])
	match := subtle.ConstantTimeCompare(expectedTag, ciphertext[offset:])
	if match != 1 {
		return nil, errors.New("square/go-jose: invalid ciphertext (auth tag mismatch)")
	}

	cbc := cipher.NewCBCDecrypter(ctx.blockCipher, nonce)

	// Make copy of ciphertext buffer, don't want to modify in place
	buffer := append([]byte{}, []byte(ciphertext[:offset])...)

	if len(buffer)%ctx.blockCipher.BlockSize() > 0 {
		return nil, errors.New("square/go-jose: invalid ciphertext (invalid length)")
	}

	cbc.CryptBlocks(buffer, buffer)

	// Remove padding
	plaintext, err := unpadBuffer(buffer, ctx.blockCipher.BlockSize())
	if err != nil {
		return nil, err
	}

	ret, out := resize(dst, len(dst)+len(plaintext))
	copy(out, plaintext)

	return ret, nil
}
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.