CVE-2021-39341

HIGH EXPLOITED NUCLEI

Optinmonster < 2.6.4 - Incorrect Authorization

Title source: rule

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.

Nuclei Templates (1)

OptinMonster Plugin < 2.6.5 - Unprotected REST-API

HIGHVERIFIEDby iamnoooob,pdresearch

References (3)

[Exploit, Third Party Advisory] https://www.wordfence.com/blog/2021/10/1000000-sites-affected-by-optinmonster-vulnerabilities/

[Third Party Advisory] https://wordfence.com/vulnerability-advisories/#CVE-2021-39341

[Third Party Advisory] https://plugins.trac.wordpress.org/browser/optinmonster/trunk/OMAPI/RestApi.php?rev=2606519#L1460

Scores

CVSS v3 8.2

EPSS 0.4432

EPSS Percentile 97.6%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

VulnCheck KEV 2021-10-27

CWE

CWE-319 CWE-285 CWE-863

Status published

Products (1)

optinmonster/optinmonster < 2.6.4

Published Nov 01, 2021

Tracked Since Feb 18, 2026