CVE-2026-21483

listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

MEDIUM
5.4
CVSS Score
Published: January 2, 2026 at 08:57 PM UTC
Updated: June 17, 2026 at 10:18 AM UTC
2 products affected across 2 vendorsListmonkListmonk

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.0.0
v < 6.0.0
Affected range stops below 6.0.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/knadh/listmonk/security/advisories/GHSA-jmr4-p576-v565

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Vector?

Quick Info

StatusANALYZED
CWE
CWE-79

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