What’s Vulnerable › Vulnerabilities

CVE-2025-13993: MailerLite – Signup forms (official) <= 1.7.16 - Authenticated (Administrator+) Stored Cross-Site Scripting

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-12 · updated 2026-10-07
• Weakness: CWE-79

Description

The MailerLite – Signup forms (official) plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'form_description' and 'success_message' parameters in versions up to, and including, 1.7.16 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator access or higher, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Affected products

• MailerLite – Signup forms (official): through 1.7.16

References

• https://plugins.trac.wordpress.org/browser/official-mailerlite-sign-up-forms/tags/1.7.14/src/Controllers/AdminController.php#L179
• https://plugins.trac.wordpress.org/browser/official-mailerlite-sign-up-forms/tags/1.7.14/src/Controllers/AdminController.php#L224
• https://plugins.trac.wordpress.org/browser/official-mailerlite-sign-up-forms/tags/1.7.14/src/Views/CustomForm.php#L38
• https://plugins.trac.wordpress.org/browser/official-mailerlite-sign-up-forms/tags/1.7.14/src/Views/CustomForm.php#L94
• https://plugins.trac.wordpress.org/changeset/3416100/official-mailerlite-sign-up-forms/trunk/src/Controllers/AdminController.php
• https://www.wordfence.com/threat-intel/vulnerabilities/id/8c37cc28-fde0-45c6-b49c-d6dfb296c4a5?source=cve

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