check_admin_referer() – Function | Developer.WordPress.org

Ensures intent by verifying that a user was referred from another admin page with the correct security nonce.

Description

This function ensures the user intends to perform a given action, which helps protect against clickjacking style attacks. It verifies intent, not authorization, therefore it does not verify the user’s capabilities. This should be performed with current_user_can() or similar.

If the nonce value is invalid, the function will exit with an "Are You Sure?" style message.

Parameters

$actionint|stringoptional: The nonce action.
Default:-1
$query_argstringoptional: Key to check for nonce in $_REQUEST. Default '_wpnonce'.
Default:'_wpnonce'

Return

int|false 1 if the nonce is valid and generated between 0-12 hours ago, 2 if the nonce is valid and generated between 12-24 hours ago.
False if the nonce is invalid.

More Information

Using the function without the $action argument is obsolete and, as of Version 3.2, if WP_DEBUG is set to true, the function will die with an appropriate message (“You should specify a nonce action to be verified by using the first parameter.” is the default).
As of 2.0.1, the referer is checked only if the $action argument is not specified (or set to the default -1) as a backward compatibility fallback for not using a nonce. A nonce is prefered to unreliable referers and with $action specified the function behaves the same way as wp_verify_nonce() except that it dies after calling wp_nonce_ays() if the nonce is not valid or was not sent.

Source

function check_admin_referer( $action = -1, $query_arg = '_wpnonce' ) {
	if ( -1 === $action ) {
		_doing_it_wrong( __FUNCTION__, __( 'You should specify an action to be verified by using the first parameter.' ), '3.2.0' );
	}

	$adminurl = strtolower( admin_url() );
	$referer  = strtolower( wp_get_referer() );
	$result   = isset( $_REQUEST[ $query_arg ] ) ? wp_verify_nonce( $_REQUEST[ $query_arg ], $action ) : false;

	/**
	 * Fires once the admin request has been validated or not.
	 *
	 * @since 1.5.1
	 *
	 * @param string    $action The nonce action.
	 * @param false|int $result False if the nonce is invalid, 1 if the nonce is valid and generated between
	 *                          0-12 hours ago, 2 if the nonce is valid and generated between 12-24 hours ago.
	 */
	do_action( 'check_admin_referer', $action, $result );

	if ( ! $result && ! ( -1 === $action && str_starts_with( $referer, $adminurl ) ) ) {
		wp_nonce_ays( $action );
		die();
	}

	return $result;
}

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Hooks

do_action( ‘check_admin_referer’, string $action, false|int $result ): Fires once the admin request has been validated or not.

Uses	Description
wp_verify_nonce()`wp-includes/pluggable.php`	Verifies that a correct security nonce was used with time limit.
wp_nonce_ays()`wp-includes/functions.php`	Displays “Are You Sure” message to confirm the action being taken.
wp_get_referer()`wp-includes/functions.php`	Retrieves referer from ‘_wp_http_referer’ or HTTP referer.
_doing_it_wrong()`wp-includes/functions.php`	Marks something as being incorrectly called.
admin_url()`wp-includes/link-template.php`	Retrieves the URL to the admin area for the current site.
do_action()`wp-includes/plugin.php`	Calls the callback functions that have been added to an action hook.

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Used by	Description
use_block_editor_for_post()`wp-includes/post.php`	Returns whether the post can be edited in the block editor.
WP_Privacy_Requests_Table::process_bulk_action()`wp-admin/includes/class-wp-privacy-requests-table.php`	Process bulk actions.
_wp_personal_data_handle_actions()`wp-admin/includes/privacy-tools.php`	Handle list table actions.
set_screen_options()`wp-admin/includes/misc.php`	Saves option for number of rows when listing posts, pages, comments, etc.
wp_dashboard_setup()`wp-admin/includes/dashboard.php`	Registers dashboard widgets.
media_upload_form_handler()`wp-admin/includes/media.php`	Handles form submissions for the legacy media uploader.
wp_media_upload_handler()`wp-admin/includes/media.php`	Handles the process of uploading media.
Custom_Image_Header::step_2()`wp-admin/includes/class-custom-image-header.php`	Displays second step of custom header image page.
Custom_Image_Header::step_3()`wp-admin/includes/class-custom-image-header.php`	Displays third step of custom header image page.
Custom_Image_Header::take_action()`wp-admin/includes/class-custom-image-header.php`	Executes custom header modification.
Custom_Background::take_action()`wp-admin/includes/class-custom-background.php`	Executes custom background modification.
Custom_Background::handle_upload()`wp-admin/includes/class-custom-background.php`	Handles an Image upload for the background image.

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Changelog

Version	Description
2.5.0	The `$query_arg` parameter was added.
1.2.0	Introduced.

User Contributed Notes

Skip to note 3 content

Codex 9 years ago

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Usage in a plugin’s option page

Here is an example of how you might use this in a plugin’s option page. You add a nonce to a form using the wp_nonce_field() function:
```
<form method="post">
   
   <?php wp_nonce_field( 'name_of_my_action','name_of_nonce_field' ); ?>
</form>
```
Then in the page where the form submits to, you can verify whether or not the form was submitted and update values if it was successfully submitted:
```
<?php
// if this fails, check_admin_referer() will automatically print a "failed" page and die.
if ( ! empty( $_POST ) && check_admin_referer( 'name_of_my_action', 'name_of_nonce_field' ) ) {
   // process form data, e.g. update fields
}

// Display the form
```
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Skip to note 4 content

Codex 9 years ago

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Note – Obsolete usage

script dies if the admin referer is not validated.
```
<?php check_admin_referer(); ?>
```
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check_admin_referer( int|string $action = -1, string $query_arg = ‘_wpnonce’ ): int|false

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