GitHub Advisoryadvisory · Go

GHSA-34g8-9fpp-46ch Mattermost fails to limit the size of responses from integration action endpoints

MEDIUM Published 2026-03-16 Modified 2026-03-17 Official page ↗
Aliases
CVE-2026-2456
Ecosystem
Go
Packages
github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Weaknesses
CWE-789
Reviewed
2026-03-17

Affected packages

• Go github.com/mattermost/mattermost/server/v8: < 8.0.0-20260127165411-fe3052073dc6 → fixed in 8.0.0-20260127165411-fe3052073dc6 • Go github.com/mattermost/mattermost-server: < 5.3.2-0.20260127165411-fe3052073dc6 → fixed in 5.3.2-0.20260127165411-fe3052073dc6 • Go github.com/mattermost/mattermost-server: >= 10.11.0-rc1, < 10.11.11 → fixed in 10.11.11 • Go github.com/mattermost/mattermost-server: >= 11.2.0-rc1, < 11.2.3 → fixed in 11.2.3 • Go github.com/mattermost/mattermost-server: >= 11.3.0-rc1, < 11.3.1 → fixed in 11.3.1

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

Related

Alias · CVE (1)

  • CVE-2026-2456 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… vulnerability

Weakness · CWE (1)

  • CWE-789 Memory Allocation with Excessive Size Value weakness

References