# Newsletters <= 4.18.2 - Unauthenticated SQL Injection via 'instance[lists]' Parameter

- **ID:** WPSEC-2026-2987
- **Plugin:** Newsletters (`newsletters-lite`), https://wordpress.org/plugins/newsletters-lite/
- **Affected versions:** all versions before 4.18.3
- **Fixed in:** 4.18.3 (Update to 4.18.3 or later.)
- **Severity:** High 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
- **Weakness:** CWE-89
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-12)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/newsletters-lite
- **Fix released:** 2026-11-10
- **Published:** 2026-11-12
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2987/

## Description

The Newsletters plugin for WordPress is vulnerable to SQL Injection via the 'instance[lists]' parameter of the front-end AJAX field refresh action in all versions up to, and including, 4.18.2 due to insufficient escaping of the user-supplied mailing list IDs and the lack of preparation of the mailing list selection query. This makes it possible for unauthenticated attackers, using the nonce exposed on public pages, to append additional SQL queries to existing queries and extract sensitive information from the database.

## References

- https://wpsec.com/vuln/WPSEC-2026-2987/
- https://plugins.svn.wordpress.org/newsletters-lite/tags/4.18.3/
- https://wordpress.org/plugins/newsletters-lite/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2987/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.