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Description

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

PUBLISHED Reserved 2026-05-29 | Published 2026-07-13 | Updated 2026-07-13 | Assigner Mattermost




MEDIUM: 5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

Problem types

CWE-862: Missing Authorization

Product status

Default status
unaffected

11.7.0 (semver)
affected

11.6.0 (semver)
affected

10.11.0 (semver)
affected

11.8.0
unaffected

11.7.3
unaffected

11.6.5
unaffected

10.11.20
unaffected

Credits

se1en finder

References

mattermost.com/security-updates (MMSA-2026-00688) vendor-advisory

cve.org (CVE-2026-10085)

nvd.nist.gov (CVE-2026-10085)

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