CVE-2026-66358

Deferred Deferred - Pending Action

Cross-Site Scripting (XSS) Vulnerability in acmailer

Publication date: 2026-08-19

Last updated on: 2026-08-28

Assigner: JPCERT/CC

Description

A cross-site scripting vulnerability exists in acmailer, which may allow an attacker to execute an arbitrary script.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-19

Last Modified

2026-08-28

Generated

2026-09-08

AI Q&A

2026-08-19

EPSS Evaluated

2026-09-07

NVD

CVE-2026-66358

EUVD

EUVD-2026-62237

Affected Vendors & Products

Vendor	Product	Version / Range
extra_innovation_inc	acmailer	4.1.2
extra_innovation_inc	acmailer	1.2.2
extra_innovation_inc	acmailer	to 4.1.2 (exc)
extra_innovation_inc	acmailer	to 1.2.2 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This is a cross-site scripting (XSS) vulnerability in acmailer, a free email delivery software. It allows an attacker to inject malicious scripts into web pages viewed by users, potentially stealing data or performing unauthorized actions.

Detection Guidance

To detect this XSS vulnerability in acmailer, check if your system is running affected versions (CGI prior to 4.1.2 or DB prior to 1.2.2). Inspect web server logs for unusual script execution patterns or unauthorized input submissions. Use tools like OWASP ZAP or Burp Suite to scan for XSS flaws in acmailer's web interface.

Impact Analysis

An attacker could exploit this to run arbitrary scripts in your browser when you access acmailer, leading to session hijacking, data theft, or defacement of web pages. Users of vulnerable versions should update immediately.

Compliance Impact

This XSS vulnerability could expose user data, violating GDPR's data protection requirements or HIPAA's safeguards for sensitive information. Organizations must patch to maintain compliance.

Mitigation Strategies

Immediately update acmailer to CGI version 4.1.2 or later and DB version 1.2.2 or later. Disable or restrict access to acmailer until updates are applied. Monitor network traffic for suspicious activity and review user permissions to prevent unauthorized access.

Hi! I’m here to help you understand CVE-2026-66358. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70