CVE-2026-10085
Ordinary group/direct message member can enable group_constrained and remove all channel participants
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Ordinary group/direct message member can enable group_constrained and remove all channel participants
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
- Record
CVE-2026-10085- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L - Weakness
- CWE-862
- Updated
- 2026-11-02
EUVDEUVD-2026-43311
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
- Record
EUVD-2026-43311- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6v2h-jj3h-8gmx
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the...
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
- Record
GHSA-6v2h-jj3h-8gmx- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L - Weakness
- CWE-862
- Updated
- 2026-11-02
NVD
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
- Record
CVE-2026-10085- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L - Weakness
- CWE-862
- Updated
- 2026-11-02
OSV
Ordinary group/direct message member can enable group_constrained and remove all channel participants
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels that support group synchronization, which allows an ordinary group or direct message member to remove all participants from the conversation via the channel patch API.. Mattermost Advisory ID: MMSA-2026-00688
- Record
CVE-2026-10085- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L - Weakness
- CWE-862
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-10085 is a medium vulnerability (CVSS 5.4) in Mattermost, published July 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.29%, the 21st percentile. No source names a fixed version.