Threat intelligence

Newsletter – Send awesome emails from WordPress <= 9.3.3 - Unauthenticated Stored Cross-Site Scripting

CVE-2026-66596 · newsletter

Important: Seeing this vulnerability listed does not mean your website is affected. Exposure depends on whether you run Newsletter at a vulnerable version. How SiteRespond intelligence works

Vulnerability: Newsletter – Send awesome emails from WordPress <= 9.3.3 - Unauthenticated Stored Cross-Site Scripting
Affected software: newsletter(Plugin)
Affected versions: ≤ 9.3.3
Authentication: Unauthenticated
Vulnerability type: Cross-site scripting
CVE: CVE-2026-66596
Published: 19 August 2026
CISA KEV: Not listed in CISA KEV at last catalog refresh
Impact: May allow attackers to run scripts in visitors' browsers or hijack admin sessions.
Source: Data imported from Wordfence Intelligence (advisory 2f715ba3-7f86-42b7-81fc-3bbaa76ae671). Methodology and redistribution notes

Check whether your installed version is affected

SiteRespond Defence matches your installed Newsletter version against this catalog when the Defence plugin is connected to your WordPress site.

Start SiteRespond Defence for WordPress — £29.99/monthScan your website

All Newsletter advisoriesBack to catalog