CVE-2026-81764: CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Acato Email Essentials

CVE-2026-81764 is an unauthenticated cross-site scripting (XSS) vulnerability affecting Acato Email Essentials versions up to and including 6.0.6. The issue stems from improper neutralization of input during web page generation (CWE-79), which could allow attackers to inject malicious scripts that execute in the context of the affected application. The CVSS 3.1 vector indicates the vulnerability is remotely exploitable over the network without privileges, requires user interaction, and impacts confidentiality, integrity, and availability at a low level with scope change.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary scripts in the context of the vulnerable application, potentially leading to information disclosure, modification of data, or disruption of service. The vulnerability affects confidentiality, integrity, and availability to a limited extent. No active exploitation has been reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should exercise caution with untrusted input and consider applying any vendor-recommended workarounds once published.