Release announcements, Security

Zulip Server 8.1 security release

Tim Abbott 3 min read

We released Zulip Server 8.1 today! This is a security release, containing important security fixes and cherry-picked changes since Zulip Server 8.0.


We recommend that all installations upgrade to this new release. See the upgrade instructions in the Zulip documentation. If you need help, best-effort support is available on

Notable changes

  • CVE-2024-21630: Zulip version 8.0 and its betas had a bug affecting an unlikely permissions configuration where some user roles had permission to create reusable invitation links to join the organization, but lacked the permission to subscribe other users to streams. A user with such a role could incorrectly create an invitation link that subscribes new users to streams. This vulnerability is similar to CVE-2023-32677, but applies to multi-use invitations, not single-user invites.
  • Fixed a fault-tolerance bug, where failing outgoing email authentication could cause other queue workers to not progress properly on low-memory Zulip servers.
  • Added support for using PostgreSQL 16 as the database. See the PostgreSQL upgrade documentation if you’re interested in upgrading an existing server to newer PostgreSQL.
  • Added support for explicitly deactivating a mobile push notifications registration.
  • Added support for a new class of custom authentication hook.
  • Improved the workflow for sending password reset emails to users imported from another chat app.
  • Improved the file uploads integration to be compatible with S3 alternatives that use a different URL addressing style.
  • Improved the Terms of Service/Privacy Policy settings if no policies sidebar is configured.
  • Fixed a bug preventing the incoming email integration from mentioning groups that everyone is allowed to mention.
  • Fixed the data import tool crashing when processing delivered scheduled messages.
  • Fixed buggy tooltips in the push notifications column of notification settings.
  • Fixed minor UI bugs with the user group settings panel.
  • Fixed minor UI bugs with the new compose box buttons.
  • Fixed minor UI bugs with limiting guest user access to other users.
  • Fixed incorrect alert words color in the dark theme.
  • Fixed a few subtle bugs with the Zulip plan management login flow.
  • Fixed a live-update bug involving user statuses enabled via the API.
  • Fixed a configuration problem preventing the logrotate service from starting.
  • Fixed a layout bug for the mobile help center navbar area affecting some servers.
  • Fixed Slack data import tool corner cases involving shared users.
  • Fixed mentions being incorrectly converted to silent mentions in DMs with bot users.
  • Fixed an unexploitable HTML injection bug in the typeahead for configuring custom code playgrounds.
  • Improved in-app documentation for following topics.
  • Backported several documentation improvements.


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