CVE-2026-21483CWE-79

listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

Medium · published January 2, 2026

CVSS v4.0
5.4
EPSS
0%
Percentile
12.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
5.4 · MEDIUM
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
EPSS
0.00226 · 12.5th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-01-02T20:57Z
EPSS history
Timeline
  • 02 JAN 20:57Z
    listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover
    cvelistv5