CVE-2026-40300
Medium
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Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages.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.
SeverityMedium
CVSS6.5
Exploit probability—
Product
Zulip Server
PublishedMay 12, 2026
First seenMay 12, 2026
Weakness typeCWE-284Improper access control
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| zulip zulip_server | 10.0 | — |
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