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CVE-2026-93849 Details

Description

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 Mattermost fail to apply allocation limits to the byte-string decode paths in its WebSocket msgpack decoder, which allows an authenticated remote attacker to cause excessive server memory allocation via a crafted binary WebSocket frame declaring a Bin32 payload length of up to 4,294,967,295 bytes.. Mattermost Advisory ID: MMSA-2026-00768

Metrics

CVSS 3.x Severity and Vector Strings:

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-789	Memory Allocation with Excessive Size Value	[email protected]

Affected Products

Product	Versions
mattermost mattermost server	>= 11.7.0, < 11.7.11 >= 11.8.0, < 11.8.6 >= 11.9.0, < 11.9.2 >= 11.10.0, < 11.10.2
CPE cpe:2.3:a:mattermost:mattermost_server:::::::: Remediation No remediation found in references.

Change History

3 change records found show changes

Date	Action	Recorded By
Nov 2, 2026	Initial Analysis	[email protected]
Oct 26, 2026	CVE Modified	CISA-ADP
Oct 26, 2026	New CVE Received	[email protected]