quantumcloud WPBot Plugin up to 8.5.9 on WordPress AJAX wpcs_send_email recipient/subject/body improper authorization

Summaryinfo

A vulnerability was found in quantumcloud WPBot Plugin up to 8.5.9. It has been declared as critical. Affected is the function wpcs_send_email of the component AJAX Handler. The manipulation of the argument recipient/subject/body results in improper authorization. This vulnerability is cataloged as CVE-2026-16774. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in quantumcloud WPBot Plugin up to 8.5.9. Affected is the function wpcs_send_email of the component AJAX Handler. The manipulation of the argument recipient/subject/body with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on integrity, and availability. CVE summarizes:

The Chatbot plugin for WordPress is vulnerable to Missing Authorization in versions up to, and including, 8.5.9 via the wpcs_send_email() AJAX handler. This is due to the wpcs_send_email() function being registered on both wp_ajax_wpcs_send_email and wp_ajax_nopriv_wpcs_send_email with no nonce verification, capability check, or rate limiting, while forwarding attacker-controlled recipient, subject, and body directly to wp_mail(). This makes it possible for unauthenticated attackers to send arbitrary emails to any recipient from the site's domain, enabling spam, phishing, and abuse that can lead to the site's IP/domain being blacklisted.

The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-16774 since 07/23/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/28/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• quantumcloud

Name

• WPBot Plugin

Version

• 8.5.0
• 8.5.1
• 8.5.2
• 8.5.3
• 8.5.4
• 8.5.5
• 8.5.6
• 8.5.7
• 8.5.8
• 8.5.9

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Once again VulDB remains the best source for vulnerability data.

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