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TI-2026-17337 Aliases CVE-2026-21483GHSA-jmr4-p576-v565

listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover

Priority MEDIUM 64CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00226 13th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed listmonk (knadh): 6.0.0github.com/knadh/listmonk (Go): 6.0.0, 1.1.1-0.20251231125615-74dc5a01cfbb

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
knadhlistmonkbefore 6.0.06.0.0Patch availableCNA
—github.com/knadh/listmonk (Go)1.1.1 to before 6.0.06.0.0Patch availableGHSA-jmr4-p576-v565
—github.com/knadh/listmonk (Go)before 1.1.1-0.20251231125615-74dc5a01cfbb1.1.1-0.20251231125615-74dc5a01cfbbPatch availableGHSA-jmr4-p576-v565
  • listmonk Vendorknadh Affected before 6.0.0 Fixed in 6.0.0 Patch available CNA
  • github.com/knadh/listmonk (Go) Vendor— Affected 1.1.1 to before 6.0.0 Fixed in 6.0.0 Patch available GHSA-jmr4-p576-v565
  • github.com/knadh/listmonk (Go) Vendor— Affected before 1.1.1-0.20251231125615-74dc5a01cfbb Fixed in 1.1.1-0.20251231125615-74dc5a01cfbb Patch available GHSA-jmr4-p576-v565

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nadh:listmonk:*:*:*:*:*:*:*:*before 6.0.0Vulnerableknadh
  • cpe:2.3:a:nadh:listmonk:*:*:*:*:*:*:*:* Versions before 6.0.0 Vulnerable ·knadh

Remediation

  • Fix · CNA listmonk (knadh) Fixed in 6.0.0
  • Fix · GHSA-jmr4-p576-v565 github.com/knadh/listmonk (Go) Fixed in 6.0.0 Advisory →
  • Fix · GHSA-jmr4-p576-v565 github.com/knadh/listmonk (Go) Fixed in 1.1.1-0.20251231125615-74dc5a01cfbb Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21483
  2. 2026-10-03 Alias added: GHSA-jmr4-p576-v565

References

Exploit 1

Advisory 1

Other 3

  • TI-2025-31216 listmonk's Sprig template Injection vulnerability leads to reading of Environment Variable for low privilege user CVSS 3.1CRITICAL 9.1
  • TI-2025-36190 listmonk Vulnerable to CSRF to XSS Chain That Can Lead to Admin Account Takeover CVSS 4.0HIGH 8.6
  • TI-2026-27072 listmonk: Active sessions remain valid after password reset and password change CVSS 3.1HIGH 7.1
  • TI-2025-28914 Listmonk v4.1.0 (fixed in v5.0.0) is vulnerable to SQL Injection in the QuerySubscribers… CVSS 3.1MEDIUM 6.5
  • TI-2026-26831 listmonk: Broken Access Control in CSV Import (Unauthorized List Assignment) CVSS 3.1MEDIUM 5.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences