CVE-2026-21388

Published Apr 9, 2026

Last updated 4 days ago

Overview

Description
Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00610
Source
responsibledisclosure@mattermost.com
NVD status
Analyzed
Products
mattermost_server

Risk scores

CVSS 3.1

Type
Primary
Base score
6.5
Impact score
3.6
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

responsibledisclosure@mattermost.com
CWE-770

Social media

Hype score
Not currently trending

Configurations

References

Sources include official advisories and independent security research.