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CVE-2026-4635 Details

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

CNA: [email protected]CVSS-B:6.5 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://mattermost.com/security-updates	[email protected]	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-362	Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')	[email protected]

Affected Products

Product	Versions
mattermost mattermost server	>= 10.11.0, < 10.11.15 >= 11.4.0, < 11.4.5 >= 11.5.0, < 11.5.4 >= 11.6.0, < 11.6.1
CPE cpe:2.3:a:mattermost:mattermost_server:::::::: Remediation No remediation found in references.

Change History

5 change records found show changes

Date	Action	Recorded By
Jul 23, 2026	CVE Translated	[email protected]
Jun 17, 2026	CVE Modified	[email protected]
Jun 17, 2026	CVE Modified	CISA-ADP
May 22, 2026	Initial Analysis	[email protected]
May 22, 2026	New CVE Received	[email protected]