CVE-2026-40300

MEDIUM

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

Title source: cna
STIX 2.1

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Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages.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

References (1)

Core 1
Core References

Scores

CVSS v3 6.5
EPSS 0.0025
EPSS Percentile 15.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-284
Status published
Products (2)
zulip/zulip < 12.0
zulip/zulip_server 10.0
Published May 12, 2026
Tracked Since May 12, 2026