Simple Newsletter Plugin <= 4.3.10 - Unauthenticated Stored Cross-Site Scripting via Subscriber Custom Field via Manage Preferences Form + Campaign Preview noptin_key Pivot
The Simple Newsletter Plugin – Noptin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'noptin_fields[<custom_field_merge_tag>] (e.g. first_name)' parameter in all versions up to, and including, 4.3.10 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 attack chain requires a published campaign post whose body contains a [[subscriber.*]] merge tag; the unauthenticated attacker first POSTs the entity-encoded payload to the public manage_preferences form (which issues its own nonce on the same page), then pivots execution by embedding their confirm_key in a campaign preview URL sent to a privileged user via social engineering.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Noptin – Newsletter, New Post Notifications & Email Automation | <= 4.3.10 | 4.4.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- WordPress
- Package
Noptin – Newsletter, New Post Notifications & Email Automation- Disclosed
- 09.10.2026
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - e5f8afa3-f20c-4dfb-bcc6-2682f68723ca - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Noptin – Newsletter, New Post Notifications & Email Automation
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 01.2022 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 5
Disclosures per year
- 2022: 1
- 2023: 1
- 2024: 1
- 2025: 1
- 2026: 2
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Simple Newsletter Plugin <= 4.3.10 - Unauthenticated Stored Cross-Site Scripting via Subscriber Custom Field via Manage Preferences Form + Campaign Preview noptin_key Pivot this entry
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