Auth bypass in Knadh Listmonk
CVE-2026-34584
listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0, bugs in list permission checks allows users in a multi-user environment to access to lists (which they don't have access to) under different scenarios. This only affects multi-user environments with untrusted users. This issue has been patched in version 6.1.0.
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.002 (6.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Knadh Listmonk — versions >= 4.1.0, < 6.1.0
- Nadh Listmonk
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-34584?
- CVE-2026-34584 is a medium-severity vulnerability in Knadh Listmonk, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.4/10. Published 2026-04-02.
- How severe is CVE-2026-34584?
- Medium severity. CVSS v3 base score is 5.4 out of 10.