CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NMattermost 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
Multiple vulnerabilities have been discovered in Mattermost products, including desktop apps and server versions. These vulnerabilities could allow an attacker to elevate privileges, compromise data confidentiality, and…