CVE-2021-39341

Name: CVE-2021-39341
Creator: NVD / NIST
Published: 2021-11-01T21:15:07.863+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.2/10EPSS 23.27%

Last modified Jun 17, 2026

CVE-2021-39341 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. The OptinMonster WordPress plugin is vulnerable to sensitive information disclosure and unauthorized setting updates due to insufficient authorization validation via the logged_in_or_has_api_key function in the ~/OMAPI/RestApi.php file that can used to exploit inject malicious web scripts on sites with the plugin installed. This affects versions up to, and including, 2.6.4.. EPSS estimates a 23.27% chance of exploitation in the next 30 days.

Description

The OptinMonster WordPress plugin is vulnerable to sensitive information disclosure and unauthorized setting updates due to insufficient authorization validation via the logged_in_or_has_api_key function in the ~/OMAPI/RestApi.php file that can used to exploit inject malicious web scripts on sites with the plugin installed. This affects versions up to, and including, 2.6.4.

Metrics

CVSS 3.1

8.2/10

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

EPSS Probability

23.27%

97.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Optinmonster	Optinmonster	<= 2.6.4

References

https://plugins.trac.wordpress.org/browser/optinmonster/trunk/OMAPI/RestApi.php?rev=2606519#L1460Third Party Advisory
https://wordfence.com/vulnerability-advisories/#CVE-2021-39341Third Party Advisory
https://www.wordfence.com/blog/2021/10/1000000-sites-affected-by-optinmonster-vulnerabilities/Exploit, Third Party Advisory
https://plugins.trac.wordpress.org/browser/optinmonster/trunk/OMAPI/RestApi.php?rev=2606519#L1460Third Party Advisory
https://wordfence.com/vulnerability-advisories/#CVE-2021-39341Third Party Advisory
https://www.wordfence.com/blog/2021/10/1000000-sites-affected-by-optinmonster-vulnerabilities/Exploit, Third Party Advisory

Timeline

Published: Nov 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39341?

How severe is CVE-2021-39341?

CVE-2021-39341 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 23.27% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39341?

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-2021-39341?

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

Scan your code now

Source: NVD / NIST