Strix
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CVE-2026-21483

MEDIUMCVSS 5.4/10EPSS 0.20%

Last modified

CVE-2026-21483 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS 4.0
5.4/10

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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.20%

9.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
NadhListmonk< 6.0.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-21483?
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.
How severe is CVE-2026-21483?
CVE-2026-21483 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.
How do I fix CVE-2026-21483?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21483?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST