CVE-2021-24925

Modern Events Calendar Lite <= 6.1.0 - Reflected Cross-Site Scripting via current_month_divider parameter

2021-11-15 00:00
Krzysztof Zając

Strategic Overview

Status
Patched in 6.1.5
Affected Plugin
Modern Events Calendar Lite
Affected Version
<= 6.1.0
CVSS
6.1Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2021-24925
View all Modern Events Calendar Lite vulnerabilities

At a glance

CVE-2021-24925 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Modern Events Calendar Lite WordPress plugin, affecting versions <= 6.1.0. 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 6.1.5; sites on affected versions should update now. Disclosed November 2021, reported by Krzysztof Zając.

Vulnerability Overview

The Modern Events Calendar Lite WordPress plugin before 6.1.5 does not sanitise and escape the current_month_divider parameter of its mec_list_load_more AJAX call (available to both unauthenticated and authenticated users) before outputting it back in the response, leading to a Reflected Cross-Site Scripting issue

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')

Reaching this weakness in Modern Events Calendar Lite <= 6.1.0 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 Modern Events Calendar Lite the fix is 6.1.5: builds <= 6.1.0 are affected, anything from 6.1.5 onward is not.

Remediation

Update to version 6.1.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Modern Events Calendar Lite: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Modern Events Calendar Lite 6.1.5 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24925https://www.wordfence.com/threat-intel/vulnerabilities/id/4eab9a5e-ca51-4952-9fd4-3d0046402e29https://nvd.nist.gov/vuln/detail/CVE-2021-24925

Related records

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