Vulnerability in Simple Newsletter Plugin – Noptin — CVE-2026-103482

What to do now

Update Simple Newsletter Plugin – Noptin to 4.4.0 or later.

Affected versions

• Everything up to and including 4.3.10

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.

This description is reproduced verbatim from the public vulnerability record.

• https://www.wordfence.com/threat-intel/vulnerabilities/id/e5f8afa3-f20c-4dfb-bcc6-2682f68723ca?source=api-prod

Part of this record comes from Wordfence Intelligence. Original: https://www.wordfence.com/threat-intel/vulnerabilities/id/e5f8afa3-f20c-4dfb-bcc6-2682f68723ca
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