What’s Vulnerable › Vulnerabilities

CVE-2021-39325: OptinMonster <= 2.6.0 Reflected Cross-Site Scripting

• Severity: medium (CVSS 4.3 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-20 · updated 2026-06-17
• Weakness: CWE-79

Description

The OptinMonster WordPress plugin is vulnerable to Reflected Cross-Site Scripting due to insufficient input validation in the load_previews function found in the ~/OMAPI/Output.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 2.6.0.

Affected products

• OptinMonster: through 2.6.0

References

• https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2595758%40optinmonster&new=2595758%40optinmonster&sfp_email=&sfph_mail=#file2
• https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39325
• https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2595758%40optinmonster&new=2595758%40optinmonster&sfp_email=&sfph_mail=#file2
• https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39325

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