5.4

CVE-2026-21483: listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

Analyzed
AliasesGHSA-jmr4-p576-v565GO-2026-4277
Published 02-01-2026Last modified 02-01-2026

Vulnerability summary

CVE-2026-21483 is a medium (CVSS 5.4) vulnerability in knadh listmonk. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.3% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 5.4, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.4/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:0142-1

Timeline

  1. 02-01-2026
    PublishedVulnerability first disclosed.
  2. 02-01-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.23% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Listmonk

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Github.com/knadh1 product
  • listmonk≥ 1.1.1, < 6.0.0 | < 1.1.1-0.20251231125615-74dc5a01cfbb
Knadh1 product
Nadh1 product

3 vendors · 3 products

References

5 links