How severe is CVE-2026-21483?

CVE-2026-21483 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-21483 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21483?

CVE-2026-21483 affects Nadh Listmonk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21483?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-21483 have an EU (EUVD) identifier?

Yes. CVE-2026-21483 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-0751.

When was CVE-2026-21483 published?

CVE-2026-21483 was published on 2026-01-02 and last updated on 2026-06-17.

CVE-2026-21483

CVE-2026-21483 is a medium-severity vulnerability in Nadh Listmonk with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 5.4
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-0751
Weakness: CWE-79
Affected product: Nadh Listmonk
Published: 2026-01-02
Last modified: 2026-06-17

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.

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 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-21483 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21483?: CVE-2026-21483 affects Nadh Listmonk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21483?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21483 have an EU (EUVD) identifier?: Yes. CVE-2026-21483 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-0751.
When was CVE-2026-21483 published?: CVE-2026-21483 was published on 2026-01-02 and last updated on 2026-06-17.

References

https://github.com/knadh/listmonk/security/advisories/GHSA-jmr4-p576-v565

Affected products (1)

cpe:2.3:a:nadh:listmonk:*:*:*:*:*:*:*:*

More vulnerabilities in Nadh Listmonk

CVE-2025-49136 — Critical (CVSS 9.0): listmonk is a standalone, self-hosted, newsletter and mailing list manager. Starting in version 4.0.0 and prior to…
CVE-2026-34828 — High (CVSS 7.1): listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0,…
CVE-2025-46011 — Medium (CVSS 6.5): Listmonk v4.1.0 (fixed in v5.0.0) is vulnerable to SQL Injection in the QuerySubscribers function which allows…
CVE-2025-58430 — Medium (CVSS 6.1): listmonk is a standalone, self-hosted, newsletter and mailing list manager. In versions up to and including 1.1.0,…
CVE-2026-34584 — Medium (CVSS 5.4): listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0,…

All CVEs affecting Nadh Listmonk →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →