WordPress security changelog
MEDIUM CVE-2026-90981 Deferred

Newsletter – Send awesome emails from WordPress: Reflected XSS reaches logged-in administrators

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'nn' parameter in all versions up to, and including, 9.3.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Successful exploitation requires the victim to be a logged-in administrator, as the antibot check auto-passes for authenticated users, routing the unsanitized payload through the administrator-visible output branch of dienow(). The attacker needs no login, but successful exploitation requires a logged-in administrator as the victim. The complete request route is not disclosed. Affected versions reported by the CNA: <= 9.3.8. Official changelog review confirms 9.3.9 as a fixed release for this issue.

CVE / CNA score 6.1 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Newsletter – Send awesome emails from WordPress
Plugin slug
newsletter
Affected
<= 9.3.8
Safe version
9.3.9
Published
Sep 18, 2026
Weakness
CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This CVE was published Sep 18, 2026 and is one of 21 known issues for this plugin.

What to do

Update, patch or deactivate.

The official changelog confirms a fix in 9.3.9: Fixes the vulnerability in displaying the spam-reason message. Update to that release or a later supported version. Official changelog: https://wordpress.org/plugins/newsletter/#developers Escape the nn-derived spam-reason output in dienow() and keep validation consistent for authenticated visitors; do not rely on the antibot bypass to make input trustworthy.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical description

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'nn' parameter in all versions up to, and including, 9.3.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Successful exploitation requires the victim to be a logged-in administrator, as the antibot check auto-passes for authenticated users, routing the unsanitized payload through the administrator-visible output branch of dienow().

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

Primary and upstream sources