CVE-2026-9693
Mattermost thread memberships persist after team removal, exposing private channel thread metadata on re-invite
Description
Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682
INFO
Published Date :
Aug. 17, 2026, 10:07 p.m.
Last Modified :
Aug. 17, 2026, 10:07 p.m.
Remotely Exploit :
Yes !
Source :
Mattermost
Affected Products
The following products are affected by CVE-2026-9693
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee |
Solution
- Update Mattermost to a fixed version.
- Verify user access controls.
- Review thread membership data.
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The following list is the news that have been mention
CVE-2026-9693 vulnerability anywhere in the article.