CVE-2026-84740

The Events Calendar 6.12.0 - 6.17.5 - Unauthenticated Arbitrary Shortcode Execution

2026-09-28 00:00
Jakub Herman

Strategic Overview

Status
Patched in 6.17.5.1
Affected Plugin
The Events Calendar
Affected Version
6.12.0 – 6.17.5
CVSS
6.5Medium
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE-2026-84740
View all The Events Calendar vulnerabilities

At a glance

CVE-2026-84740 is a medium-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the The Events Calendar WordPress plugin, affecting versions 6.12.0 – 6.17.5. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 6.17.5.1; sites on affected versions should update now. Disclosed September 2026, reported by Jakub Herman.

Vulnerability Overview

The The Events Calendar plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions 6.12.0 through 6.17.5. This is due to the use of do_shortcode() on user supplied input. This makes it possible for unauthenticated attackers to execute arbitrary shortcodes registered on the site. The impact depends on which shortcodes the site has registered, so a site running a plugin whose shortcodes expose data or perform actions is affected more severely.

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, and no interaction from a victim user.

CWE-94: Improper Control of Generation of Code ('Code Injection')

The Events Calendar 6.12.0 – 6.17.5 carries this weakness at do_shortcode(), and reaching it takes no account at all. Code injection means input from a request reaches a language construct that evaluates code, so the attacker's text is executed rather than treated as data.

The injected code runs with the web server's privileges, giving the attacker the same access to the database and filesystem as WordPress itself. For The Events Calendar the fix is 6.17.5.1: builds 6.12.0 – 6.17.5 are affected, anything from 6.17.5.1 onward is not.

Remediation

Update to version 6.17.5.1, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: The Events Calendar 6.17.5.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2026-84740https://www.wordfence.com/threat-intel/vulnerabilities/id/fe25393e-a049-412f-962b-0c24492026bchttps://nvd.nist.gov/vuln/detail/CVE-2026-84740

Related records

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