CVE-2026-100404
Zulip is an open-source team collaboration tool.
Published Oct 14, 2026 · updated Oct 14, 2026
Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, guest users can receive new message events for public channels outside their subscriptions. A guest can trigger the issue by registering an event queue with parameters that request messages from an unsubscribed public channel, or an existing event queue can remain affected after the guest's access to the channel is removed. The flaw discloses new public-channel messages to the guest. This issue is fixed in version 12.2.
Timeline
Detection, updates, and resolution for this record.
Oct 14, 2026 · NIST NVD
Detected
Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, guest users can receive new message events for public channels outside their subscriptions. A guest can trigger the issue by registering an event queue with parameters that request messages from an unsubscribed public channel, or an existing event queue can remain affected after the guest's access to the channe
Sources
- CVE.orgCVE-2026-100404
Official CVE identifier
cve.org - NIST NVDCVE-2026-100404
Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, guest users can receive new message events for public channels outside their subscriptions. A guest can trigger the issue by registering an event queue with parameters that request messages fr
nvd.nist.gov