CVE-2026-6046

Published Jun 12, 2026

Last updated a day ago

Overview

Description
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649
Source
responsibledisclosure@mattermost.com
NVD status
Received

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.3
Impact score
3.6
Exploitability score
1.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Severity
MEDIUM

Weaknesses

responsibledisclosure@mattermost.com
CWE-200

Social media

Hype score
Not currently trending

References

Sources include official advisories and independent security research.