CVE-2026-40300 MEDIUM

CVE-2026-40300: Zulip: Message edit history visible in "moves only" policy through /api/v1/messages/{id}/history

Vendor Zulip
Product zulip
Weakness CWE-284
Published May 12, 2026
Last update May 13, 2026
View on NVD All CVEs

CVSS base score

6.0/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality —
Integrity —

CVSS vector

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

What the vulnerability does

01Description

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Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages.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.

Key dates

02Disclosure timeline

May 12, 2026 CVE published
May 13, 2026 Record updated