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 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661
CVSS breakdown
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
Low
Affected products
- Mattermost / Mattermost11.6.0 – 11.6.1
- Mattermost / Mattermost11.5.0 – 11.5.4
- Mattermost / Mattermost10.11.0 – 10.11.15
- Mattermost / Mattermost10.11.0 – 10.11.16
- Mattermost / Mattermost11.7.0 – 11.7.0
- Mattermost / Mattermost11.6.2 – 11.6.2
- Mattermost / Mattermost11.5.5 – 11.5.5
- Mattermost / Mattermost10.11.16 – 10.11.16
- Mattermost / Mattermost10.11.17 – 10.11.17