CVE-2026-17089

Events Manager <= 7.4.0.1 - Reflected Cross-Site Scripting via 'header_format' Parameter

2026-08-24 14:30
Wordfence PRISM

Strategic Overview

Status
Patched in 7.4.1
Affected Plugin
Events Manager – Calendar, Bookings, Tickets, and more!
Affected Version
<= 7.4.0.1
CVSS
6.1Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-17089
View all Events Manager – Calendar, Bookings, Tickets, and more! vulnerabilities

At a glance

CVE-2026-17089 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Events Manager WordPress plugin, affecting versions <= 7.4.0.1. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 7.4.1; sites on affected versions should update now. Disclosed August 2026, reported by Wordfence PRISM.

Vulnerability Overview

The Events Manager – Calendar, Bookings, Tickets, and more! plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'header_format' parameter in all versions up to, and including, 7.4.0.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The shortcode entry point sanitizes 'header_format' via wp_kses(), but the unauthenticated 'search_events_grouped' AJAX action bypasses this sanitization entirely, leaving the parameter unsanitized before it is echoed into the HTML body in output_grouped().

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Events Manager <= 7.4.0.1 carries this weakness at header_format, and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Events Manager the fix is 7.4.1: builds <= 7.4.0.1 are affected, anything from 7.4.1 onward is not.

Remediation

Update to version 7.4.1, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Events Manager: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Events Manager 7.4.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-17089https://www.wordfence.com/threat-intel/vulnerabilities/id/a56d1a9e-7564-41b0-af03-c272ffbbbb97https://nvd.nist.gov/vuln/detail/CVE-2026-17089

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C