CVE-2026-10103
Authenticated remote cluster can modify or delete posts it does not own in Mattermost Connected Workspaces shared channels
CVSS Score
4.3
EPSS Score
0.1%
EPSS Percentile
4th
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
| CWE | CWE-639 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Jul 13, 2026 |
| Last Updated | Jul 14, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Affected Versions
Mattermost / Mattermost
11.7.0 ≤ 11.7.2 11.6.0 ≤ 11.6.4 10.11.0 ≤ 10.11.19
Credits
ratrarity