CVE-2026-21483: medium-severity vulnerability in knadh listmonk
listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover
Published
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.4epss 0.2%
exploitation probability
0.2%top 88% of all CVEs
observed exploitation
nono source reports it
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.
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
Affected products
knadh · listmonkRelated CVEs — knadh listmonk
In the same product, most dangerous first.
CVE-2025-49136CRITICALlistmonk's Sprig template Injection vulnerability leads to reading of Environment Variable for low privilege userEPSS 1.5%CVE-2026-62361MEDIUMlistmonk: SQL Injection in `/api/subscribers/export` bypasses table access control, leaking admin password hashes and SMTP credentialsEPSS 0.4%CVE-2026-34828HIGHlistmonk: Active sessions remain valid after password reset and password changeEPSS 0.4%CVE-2026-34584MEDIUMlistmonk: Broken Access Control in CSV Import (Unauthorized List Assignment)EPSS 0.3%CVE-2025-58430HIGHlistmonk Vulnerable to CSRF to XSS Chain That Can Lead to Admin Account TakeoverEPSS 0.1%