/api/v1/jwt/fetch_api_key endpoint can leak if an email address has an account in Zulip server

Vulnerability Description

Zulip server provides an open-source team chat that helps teams stay productive and focused. Zulip Server 7.0 and above are vulnerable to an information disclose attack, where, if a Zulip server is hosting multiple organizations, an unauthenticated user can make a request and determine if an email address is in use by a user. Zulip Server 9.4 resolves the issue, as does the `main` branch of Zulip Server. Users are advised to upgrade. There are no known workarounds for this issue.

References

• https://github.com/zulip/zulip/security/advisories/GHSA-5xg8-xhfj-4hm6
• https://github.com/zulip/zulip/commit/c6334a765b1e6d71760e4a3b32ae5b8367f2ed4d