XSS in Webnus Modern Events Calendar Lite

CVE-2023-4021

The Modern Events Calendar lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Google API key and Calendar ID in versions up to, but not including, 7.1.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (28.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-4021: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-4021?
CVE-2023-4021 is a medium-severity vulnerability in Webnus Modern Events Calendar Lite, classified under Cross-site Scripting. CVSS score: 4.4/10. Published 2023-10-20.
How severe is CVE-2023-4021?
Medium severity. CVSS v3 base score is 4.4 out of 10.
Is CVE-2023-4021 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.