CVE-2026-16774: Auth Bypass (CVSS 5.3)

Description

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.

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CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://plugins.trac.wordpress.org/browser/chatbot/tags/8.5.9/includes/chat-sessions/wpbot-chat-sessions.php#L478 https://plugins.trac.wordpress.org/browser/chatbot/tags/8.5.9/includes/chat-sessions/wpbot-chat-sessions.php#L483 https://plugins.trac.wordpress.org/browser/chatbot/tags/8.5.9/includes/chat-sessions/wpbot-chat-sessions.php#L494 https://plugins.trac.wordpress.org/changeset?reponame=&old=3621386%40chatbot&new=3621386%40chatbot https://www.wordfence.com/threat-intel/vulnerabilities/id/3cc6aa06-ab2a-4d5c-bbbe-4c19722ccc53?source=cve

Frequently Asked Questions

What is CVE-2026-16774? +

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-16774? +

CVE-2026-16774 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-16774? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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