CVE-2022-21706: 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...

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).

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.33%

67.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zulip	Zulip Server	>= 2.0.0, < 4.10.0

References

https://blog.zulip.com/2022/02/25/zulip-cloud-invitation-vulnerability/Vendor Advisory
https://blog.zulip.com/2022/02/25/zulip-server-4-10-security-release/#cve-2022-21706Vendor Advisory
https://github.com/zulip/zulip/commit/88917019f03860609114082cdc0f31a561503f9ePatch, Third Party Advisory
https://github.com/zulip/zulip/security/advisories/GHSA-6xmj-2wcm-p2jcThird Party Advisory
https://blog.zulip.com/2022/02/25/zulip-cloud-invitation-vulnerability/Vendor Advisory
https://blog.zulip.com/2022/02/25/zulip-server-4-10-security-release/#cve-2022-21706Vendor Advisory
https://github.com/zulip/zulip/commit/88917019f03860609114082cdc0f31a561503f9ePatch, Third Party Advisory
https://github.com/zulip/zulip/security/advisories/GHSA-6xmj-2wcm-p2jcThird Party Advisory

Timeline

Published: Feb 26, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-21706?

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).

How severe is CVE-2022-21706?

CVE-2022-21706 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.33% probability of exploitation in the next 30 days.

How do I fix CVE-2022-21706?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.