What’s Vulnerable › Vulnerabilities

CVE-2023-32678: Zulip vulnerable to insufficient authorization check for edition/deletion of messages and topics in private streams by former subscribers

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-08-25 · updated 2026-06-17
• Weakness: CWE-285

Description

Zulip is an open-source team collaboration tool with topic-based threading that combines email and chat. Users who used to be subscribed to a private stream and have been removed from it since retain the ability to edit messages/topics, move messages to other streams, and delete messages that they used to have access to, if other relevant organization permissions allow these actions. For example, a user may be able to edit or delete their old messages they posted in such a private stream. An administrator will be able to delete old messages (that they had access to) from the private stream. This issue was fixed in Zulip Server version 7.3.

Affected products

• zulip: before 7.3 — fixed in 7.3

How to fix

Upgrade to a fixed version: zulip 7.3. Check the vendor advisory for mitigations.

References

• https://github.com/zulip/zulip/security/advisories/GHSA-q3wg-jm9p-35fj
• https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-7-3
• https://github.com/zulip/zulip/security/advisories/GHSA-q3wg-jm9p-35fj
• https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-7-3

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