CVE-2026-10103

MEDIUM

Mattermost 10.11/11.6/11.7 - Shared Channel Post Ownership Bypass

Title source: manual
STIX 2.1

Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which allows an authenticated remote cluster to modify or delete posts authored by local users or other remotes via crafted sync messages referencing arbitrary post IDs in channels shared with that remote.. Mattermost Advisory ID: MMSA-2026-00689

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00689
https://mattermost.com/security-updates

Scores

CVSS v3 4.3
EPSS 0.0014
EPSS Percentile 4.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Details

CWE
CWE-639
Status published
Products (8)
Mattermost/Mattermost 10.11.0 - 10.11.19
Mattermost/Mattermost 10.11.20
Mattermost/Mattermost 11.6.0 - 11.6.4
Mattermost/Mattermost 11.6.5
Mattermost/Mattermost 11.7.0 - 11.7.2
Mattermost/Mattermost 11.7.3
Mattermost/Mattermost 11.8.0
mattermost/mattermost_server 10.11.0 - 10.11.20
Published Jul 13, 2026
Tracked Since Jul 13, 2026