CVE-2026-2456

MEDIUM

Denial of Service via Unbounded Memory Allocation in Integration Actions

Title source: cna

Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

References (1)

[Vendor Advisory] https://mattermost.com/security-updates

Scores

CVSS v3 5.3

EPSS 0.0004

EPSS Percentile 12.4%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-789

Status published

Products (10)

mattermost/mattermost 0 - 8.0.0-20260127165411-fe3052073dc6Go

Mattermost/Mattermost 10.11.0 - 10.11.10

Mattermost/Mattermost 10.11.11

Mattermost/Mattermost 11.2.0 - 11.2.2

Mattermost/Mattermost 11.2.3

Mattermost/Mattermost 11.3.0

Mattermost/Mattermost 11.3.1

Mattermost/Mattermost 11.4.0

mattermost/mattermost-server 0 - 5.3.2-0.20260127165411-fe3052073dc6Go

mattermost/mattermost_server 10.11.0 - 10.11.11

Published Mar 16, 2026

Tracked Since Mar 16, 2026