CVE-2021-30487: Zulip Server

Low severity, CVSS 2.7. EPSS: 0.7% chance of exploitation in the next 30 days.

In the topic moving API in Zulip Server 3.x before 3.4, organization administrators were able to move messages to streams in other organizations hosted by the same Zulip installation.

Affected products

• Zulip Zulip Server: from 3.0, before 3.4 (fixed in 3.4)

Published 2021-04-15. Last modified 2026-06-17.