---
id: gk-block-mcp-media-sideload-blocked-ipv6-cidrs
title: "Filter - gk/block-mcp/media/sideload-blocked-ipv6-cidrs"
sidebar_label: "gk/block-mcp/media/sideload-blocked-ipv6-cidrs"
tags:
  - "2.0.0"
---

# Filter: gk/block-mcp/media/sideload-blocked-ipv6-cidrs

Adjust which IPv6 ranges are off-limits when sideloading from a URL.

The IPv6 companion to the SSRF guard: it blocks loopback, unique-local, link-local, IPv4-mapped, and other reserved IPv6 space before any remote fetch, so a malicious URL can't reach your internal services over IPv6. Add your own CIDRs to extend the block list to ranges specific to your network. Values are standard CIDR strings (e.g. `fc00::/7`).

## Parameters

| Name | Type | Description |
|------|------|-------------|
| $v6_cidrs | `array<int,string>` | Blocked IPv6 ranges as CIDR strings. |

## Example

// Block an additional internal IPv6 prefix.

```php
add_filter( 'gk/block-mcp/media/sideload-blocked-ipv6-cidrs', function ( $cidrs ) {
    $cidrs[] = '2001:db8::/32';
    return $cidrs;
} );
```

### Since

- [2.0.0](../../since/2-0-0/)

### Source

Defined in `wordpress-plugin/gk-block-api/includes/class-media-manager.php` at line 649