Advisory Published

CVE-2023-47642: Stream description leaks to ex-subscribers in Zulip

First published: Thu Nov 16 2023(Updated: )

Zulip is an open-source team collaboration tool. It was discovered by the Zulip development team that active users who had previously been subscribed to a stream incorrectly continued being able to use the Zulip API to access metadata for that stream. As a result, users who had been removed from a stream, but still had an account in the organization, could still view metadata for that stream (including the stream name, description, settings, and an email address used to send emails into the stream via the incoming email integration). This potentially allowed users to see changes to a stream’s metadata after they had lost access to the stream. This vulnerability has been addressed in version 7.5 and all users are advised to upgrade. There are no known workarounds for this issue.


Affected SoftwareAffected VersionHow to fix
Zulip Zulip Server>=1.3.0<7.5

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Frequently Asked Questions

  • What is the vulnerability ID?

    The vulnerability ID is CVE-2023-47642.

  • What is the severity of CVE-2023-47642?

    The severity of CVE-2023-47642 is medium with a CVSS score of 4.3.

  • What is Zulip?

    Zulip is an open-source team collaboration tool.

  • How does CVE-2023-47642 affect Zulip users?

    CVE-2023-47642 allows active users who had previously been subscribed to a stream to continue accessing metadata for that stream, even after being removed from it.

  • How can Zulip users fix CVE-2023-47642?

    Zulip users can fix CVE-2023-47642 by applying the necessary updates or patches provided by Zulip to their Zulip Server installation.


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