CVE-2026-21483 MEDIUM

CVE-2026-21483: listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

Vendor Knadh
Product listmonk
Weakness CWE-79 · XSS
Published January 2, 2026
Last update January 2, 2026

CVSS base score

5.4/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:P

What the vulnerability does

01Description

listmonk is a standalone, self-hosted, newsletter and mailing list manager. Prior to version 6.0.0, lower-privileged user with campaign management permissions can inject malicious JavaScript into campaigns or templates. When a higher-privileged user (Super Admin) views or previews this content, the XSS executes in their browser context, allowing the attacker to perform privileged actions such as creating backdoor admin accounts. The attack can be weaponized via the public archive feature, where victims simply need to visit a link - no preview click required. Version 6.0.0 fixes the issue.

Key dates

02Disclosure timeline

January 2, 2026 CVE published
January 2, 2026 Record updated