The CWE-787 vulnerability is related to "Out-of-bounds Write" issues. However, based on the provided code slice, it seems that the vulnerability is not directly caused by the line `const void *sb, *se;` itself.

The line `const void *sb, *se;` is simply declaring two constant void pointers, `sb` and `se`, which are likely used to represent the start and end of a buffer or a memory region.

The root cause of the CWE-787 vulnerability is likely due to how these pointers are used later in the code. Some possible causes of the vulnerability could be:

1. **Incorrect pointer arithmetic**: If the code performs pointer arithmetic on `sb` and `se` without proper bounds checking, it may lead to an out-of-bounds write.
2. **Insufficient bounds checking**: If the code does not properly check if the memory region between `sb` and `se` is valid or if the write operation exceeds the buffer size, it may lead to an out-of-bounds write.
3. **Incorrect buffer size calculation**: If the code calculates the buffer size incorrectly, it may lead to an out-of-bounds write when writing data to the buffer.

To fix the vulnerability, you should review the code that uses these pointers and ensure that:

* Proper bounds checking is performed before writing data to the buffer.
* Pointer arithmetic is done correctly and safely.
* The buffer size is calculated correctly.

Here's an example of how to fix the vulnerability:
```c
// Assume 'data' is the data to be written to the buffer
size_t data_size = sizeof(data);
if (data_size > (size_t)(se - sb)) {
    // Handle error: data size exceeds buffer size
    return;
}

// Copy data to the buffer, ensuring not to exceed the buffer size
memcpy(sb, data, data_size);
```
Note that without the complete code, it's difficult to provide a precise fix. The above example is just a hypothetical scenario to illustrate the concept.