CVE-2025-13993 MailerLite – Signup forms (official) <= 1.7.16 - Authenticated (Administrator+) Stored Cross-Site Scripting
Authenticated administrators can inject arbitrary scripts via signup form parameters, leading to stored XSS execution for other users.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-13993?
CVE-2025-13993 is a medium-severity cross-site scripting vulnerability in MailerLite – Signup forms (official), published on 12 Dec 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2025-13993?
How do I fix CVE-2025-13993?
No fix has been published for CVE-2025-13993 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2025-13993 being exploited?
There is no known exploitation of CVE-2025-13993 in the wild and no public exploit code.
Sources
Also known as GHSA-647v-r7p3-c33c.