CVE-2025-13993

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

5.5 Medium

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: None

Exploit likelihood

0.34%Up 0.3 points since Dec 12, 2025

What each source reports

CVE List Score used 5.5

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

Record: CVE-2025-13993
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2025-203071 5.5

Record: EUVD-2025-203071
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-647v-r7p3-c33c 5.5

The MailerLite – Signup forms (official) plugin for WordPress is vulnerable to Stored Cross-Site...

Record: GHSA-647v-r7p3-c33c
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

NVD 5.5

Record: CVE-2025-13993
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

mailerlite – signup forms (official)

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-13993 is a medium vulnerability (CVSS 5.5) in Mailerlite – Signup Forms (official), published December 12, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 28th percentile. No source names a fixed version.