Simple Newsletter Plugin <= 4.3.10 - Unauthenticated Stored Cross-Site Scripting via Subscriber Custom Field via Manage Preferences Form + Campaign Preview noptin_key Pivot

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-103482
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-10 06:16:36 UTC
Updated2026-10-13 13:30:21 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

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

EPSS: 0.003130000 probability, percentile 0.223410000 (date 2026-10-12)

Problem Types: CWE-79 | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
3.1CNADECLARED5.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Picocodes Noptin Newsletter New Post Notifications Email Automation affected 4.3.10 semver Not specified

References

ReferenceSourceLinkTags
www.wordfence.com/threat-intel/vulnerabilities/id/e5f8afa3-f20c-4dfb-bcc6-2682f... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_C... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Subscribers/Ma... [email protected] plugins.trac.wordpress.org
github.com/hizzle-co/noptin/compare/4.3.10...4.4.0 [email protected] github.com
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Emails/Preview... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_C... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/vendor/hizzle/store/... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Core/Dynamic_C... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Emails/Generat... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/newsletter-optin-box/tags/4.3.10/build/Subscribers/fu... [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: crow (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-10-01T10:43:22.000ZVendor Notified
CNA2026-10-09T17:25:21.000ZDisclosed

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