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CVE-2026-40300

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

Published: May 12, 2026Updated: May 13, 2026 Sources: CVE List NVDCWE-284
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.2%
Top 84.3%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages.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

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-284NVD-CWE-noinfo

Affected Products

zulipzulip
On-premWeb App
Enterprise Software / collaboration-groupware
zulip serverzulip
On-premWeb App
Enterprise Software / collaboration-groupware
zuliposs-projectEnterprise Softwareaka zulip

Exploitability

Official Patch Available

References

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

Timeline

Published
May 12, 2026
Last Updated
May 13, 2026

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