CVE-2024-27286: zulip server Information Disclosure

Description

Zulip is an open-source team collaboration tool. When a user moves a Zulip message, they have the option to move all messages in the topic, move only subsequent messages as well, or move just a single message. If the user chose to just move one message, and was moving it from a public stream to a private stream, Zulip would successfully move the message, -- but active users who did not have access to the private stream, but whose client had already received the message, would continue to see the message in the public stream until they reloaded their client. Additionally, Zulip did not remove view permissions on the message from recently-active users, allowing the message to show up in the "All messages" view or in search results, but not in "Inbox" or "Recent conversations" views. While the bug has been present since moving messages between streams was first introduced in version 3.0, this option became much more common starting in Zulip 8.0, when the default option in the picker for moving the very last message in a conversation was changed. This issue is fixed in Zulip Server 8.3. No known workarounds are available.

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CVSS v3.1 Score

6.5

MEDIUM

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

Weakness Type (CWE)

CWE-200 CWE-200

Affected Products

Vendor	Product	Versions
zulip	zulip_server	3.0 — 8.3

References

Advisories & Patches

https://github.com/zulip/zulip/commit/3db1733310ddd944c2e690ba673232345c928eec https://github.com/zulip/zulip/commit/3db1733310ddd944c2e690ba673232345c928eec

Other References

https://github.com/zulip/zulip/security/advisories/GHSA-478x-rfqr-w4jf https://github.com/zulip/zulip/security/advisories/GHSA-478x-rfqr-w4jf

Frequently Asked Questions

What is CVE-2024-27286? +

Zulip is an open-source team collaboration tool. When a user moves a Zulip message, they have the option to move all messages in the topic, move only subsequent messages as well, or move just a single message. If the user chose to just move one message, and was moving it from a public stream to a private stream, Zulip would successfully move the message, -- but active users who did not have access to the private stream, but whose client had already received the message, would continue to see the message in the public stream until they reloaded their client. Additionally, Zulip did not remove view permissions on the message from recently-active users, allowing the message to show up in the "All messages" view or in search results, but not in "Inbox" or "Recent conversations" views. While the bug has been present since moving messages between streams was first introduced in version 3.0, this option became much more common starting in Zulip 8.0, when the default option in the picker for moving the very last message in a conversation was changed. This issue is fixed in Zulip Server 8.3. No known workarounds are available. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2024-27286? +

CVE-2024-27286 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-27286? +

CVE-2024-27286 affects products from zulip, specifically: zulip_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-27286? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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