In Zulip Server versions 7.0 and above a medium severity vulnerability CVE-2024-56136 was detected. This vulnerability allows unauthenticated attackers to determine if an email address is in use by a user on servers hosting multiple organizations. To address this issue, users should upgrade Zulip Server to version 9.4 or later. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2024-56136.