CVE-2021-34666

Name: CVE-2021-34666
Creator: NVD / NIST
Published: 2021-08-16T19:15:15.58+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.84%

Last modified Jun 17, 2026

CVE-2021-34666 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. The Add Sidebar WordPress plugin is vulnerable to Reflected Cross-Site Scripting via the add parameter in the ~/wp_sidebarMenu.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 2.0.0.. EPSS estimates a 0.84% chance of exploitation in the next 30 days.

Description

The Add Sidebar WordPress plugin is vulnerable to Reflected Cross-Site Scripting via the add parameter in the ~/wp_sidebarMenu.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 2.0.0.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.84%

53.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Add Sidebar Project	Add Sidebar	<= 2.0.0

References

https://plugins.trac.wordpress.org/browser/sidebar-adder/tags/2.0.1/wp_sidebarMenu.php#L124Exploit, Third Party Advisory
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34666Exploit, Third Party Advisory
https://plugins.trac.wordpress.org/browser/sidebar-adder/tags/2.0.1/wp_sidebarMenu.php#L124Exploit, Third Party Advisory
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34666Exploit, Third Party Advisory

Timeline

Published: Aug 16, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-34666?

How severe is CVE-2021-34666?

CVE-2021-34666 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.84% probability of exploitation in the next 30 days.

How do I fix CVE-2021-34666?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34666?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST