CVE-2026-93849

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

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://mattermost.com/security-updates

Configurations

No configuration.

History

26 Oct 2026, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-26 15:16

Updated : 2026-10-26 17:17

NVD link : CVE-2026-93849

Mitre link : CVE-2026-93849

CVE.ORG link : CVE-2026-93849

JSON object : View

Products Affected

No product.

CWE

CWE-789

Memory Allocation with Excessive Size Value

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