CVE-2026-40300

Zulip: Message edit history visible in "moves only" policy through /api/v1/messages/{id}/history

State: Published
Severity: 6.0 Medium
Published: May 12, 2026
Updated: May 13, 2026
Reserved: Apr 10, 2026

Description

Zulip is an open-source team collaboration tool. Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages. This vulnerability is fixed in 12.0.

Scores

CVSS	Score	Vector	Source
4.0	6.0 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-284 Improper Access Control

Affected Products

Product	Versions
zulipzulip	< 12.0Affected

References

https://github.com/zulip/zulip/security/advisories/GHSA-jp8f-mvv6-89cr

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