CVE-2026-21483

listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

State: Published
Severity: 5.4 Medium
Published: Jan 2, 2026
Updated: Jan 2, 2026
Reserved: Dec 29, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	5.4 Medium	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	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
listmonkknadh	< 6.0.0Affected

References

https://github.com/knadh/listmonk/security/advisories/GHSA-jmr4-p576-v565

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.