What’s Vulnerable › Vulnerabilities
CVE-2026-21483: listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover
- Severity: medium (CVSS 5.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-01-02 · updated 2026-06-17
- Weakness: CWE-79
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.
Affected products
- knadh listmonk: before 6.0.0 — fixed in 6.0.0
How to fix
Upgrade to a fixed version: knadh listmonk 6.0.0. Check the vendor advisory for mitigations.
References
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