CVE-2025-13993Network attack vector

Stored script execution via unescaped form text

Published Dec 12, 2025 · Updated Dec 12, 2025

Stored XSS in MailerLite – Signup forms (official) 1.7.16 and earlier allows remote authenticated users to inject scripts into forms. AdminController stores the form_description and success_message parameters without sufficient sanitization, and CustomForm renders the values without adequate output escaping. Administrator-level access is required; the stored script runs when a visitor opens a page containing the affected form.

CVSS severity5.5
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in MailerLite – Signup forms (official) 1.7.16 and earlier allows remote authenticated users to inject scripts into forms. AdminController stores the form_description and success_message parameters without sufficient sanitization, and CustomForm renders the values without adequate output escaping. Administrator-level access is required; the stored script runs when a visitor opens a page containing the affected form.

The record

CVE
CVE-2025-13993
Published
Dec 12, 2025
Updated
Dec 12, 2025
Vendor
MailerLite
Product
MailerLite – Signup forms (official)
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Dec 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <=1.7.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

MailerLite · MailerLite – Signup forms (official)version=* <=1.7.16

Published CVSS scores

5.5WordfenceCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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