CVE-2026-96566: Newsletter <= 9.4.0 - Unauthenticated Stored Cross-Site Scripting via 'np1' Custom Field Parameter

Vulnerability summary

CVE-2026-96566 is a high (CVSS 7.2) Cross-site Scripting vulnerability in satollo newsletter – send awesome emails from wordpress. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 19.1% of scored vulnerabilities. Fixed in 9.4.1.

Timeline

1. 02-10-2026
   PublishedVulnerability first disclosed.
2. 03-10-2026
   Last modifiedVulnerability information updated.

Description

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'np1' Custom Field Parameter in all versions up to, and including, 9.4.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The subscription endpoint (na=sa) requires no nonce, no capability check, and no CAPTCHA, and the payload can be smuggled past email-address validation by embedding the {profile_1} placeholder in the local part of the submitted address, since WordPress's is_email() permits curly braces there.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.