CVE-2026-103482

medium

Description

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.

References

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

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/vendor/hizzle/store/src/Prop.php#L626

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Subscribers/functions.php#L937

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Subscribers/Manage_Preferences.php#L255

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Emails/Preview.php#L161

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Emails/Generate/Generator.php#L548

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_Content_Tags.php#L695

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_Content_Tags.php#L507

https://plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_Content_Tags.php#L361

https://github.com/hizzle-co/noptin/compare/4.3.10...4.4.0

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-96112

Details

Source: Mitre, NVD

Published: 2026-10-10

Updated: 2026-10-10

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 5.4

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Severity: Medium