CVE-2026-40300 Details
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Prior to 12.0, With message_edit_history_visibility_policy set to "moves", /api/v1/messages/{id}/history still returns historical content values, allowing low-privilege users to recover text that was edited away from other users' messages.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.
A vulnerability in Zulip Server prior to version 12.0 allows low-privilege users to access edited message content through the API, contrary to the intended privacy policy. This occurs when the message edit history visibility policy is set to 'moves', as the API still returns historical content values, enabling recovery of text that was deliberately edited out.
Users should update to Zulip Server version 12.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 13, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/zulip/zulip/security/advisories/GHSA-jp8f-mvv6-89cr | CISA-ADP | ExploitVendor Advisory |
| https://github.com/zulip/zulip/security/advisories/GHSA-jp8f-mvv6-89cr | [email protected] | ExploitVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
| CWE-284 | Improper Access Control | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| zulip zulip server | 10.0 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 13, 2026 | Initial Analysis | [email protected] |
| May 13, 2026 | CVE Modified | CISA-ADP |
| May 12, 2026 | New CVE Received | [email protected] |