CVE-2021-39341

OptinMonster <= 2.6.4 Unprotected REST-API Endpoints

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.

Affected

OptinMonster

CVSS v3.1 WORDFENCE

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

CVSS v2.0 NVD

6.4 MEDIUMAV:N/AC:L/Au:N/C:P/I:P/A:N

EPSS

21.93% chance of exploitation in the next 30 days, 98th percentile

Nuclei

high

Published

2021-11-01

Updated

2025-03-31

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-39341.yaml

Security advisories

• https://plugins.trac.wordpress.org/browser/optinmonster/trunk/OMAPI/RestApi.php?rev=26065…
• https://wordfence.com/vulnerability-advisories/#CVE-2021-39341
• https://www.wordfence.com/blog/2021/10/1000000-sites-affected-by-optinmonster-vulnerabili…

References

• CVE Record
• NVD entry