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.

More information : https://github.com/knadh/listmonk/commit/347f5976759232c36e571cf58b4bfe33c2794f35