# WP Mailster <= 1.9.1.0 - Unauthenticated Stored Cross-Site Scripting via Email Subject and Body

- **ID:** WPSEC-2026-1272
- **Plugin:** WP Mailster (`wp-mailster`), https://wordpress.org/plugins/wp-mailster/
- **Affected versions:** all versions before 1.9.2.0
- **Fixed in:** 1.9.2.0 (Update to 1.9.2.0 or later.)
- **Severity:** High 7.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions None seen (as of 2026-10-20)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/wp-mailster
- **Fix released:** 2026-10-18
- **Published:** 2026-10-20
- **URL:** https://wpsec.com/vuln/WPSEC-2026-1272/

## Description

The WP Mailster plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the subject, sender name and HTML body of emails received by a mailing list in all versions up to, and including, 1.9.1.0. This is due to insufficient output escaping on the admin email details and resend screens. This makes it possible for unauthenticated attackers who can send an email to a list's mailbox to inject arbitrary web scripts that will execute whenever an administrator views the email's details or the resend page.

## References

- https://wpsec.com/vuln/WPSEC-2026-1272/
- https://plugins.svn.wordpress.org/wp-mailster/tags/1.9.2.0/
- https://wordpress.org/plugins/wp-mailster/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1272/

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.