Data Retention Teams Endpoint Leaks Private Team Invite ID

Summary

CVECVE-2026-91181
StatePUBLISHED
AssignerMattermost
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-14 22:16:59 UTC
Updated2026-09-14 22:16:59 UTC
DescriptionMattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data Retention Policy permission to obtain a private team's secret invite_id and email, and use it to join the team without authorization, via GET /api/v4/data_retention/policies/{policy_id}/teams.. Mattermost Advisory ID: MMSA-2026-00702

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

Problem Types: CWE-863 | CWE-863 CWE-863: Incorrect Authorization


VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
3.1CNACVSS6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mattermost Mattermost affected 11.9.0 11.9.0 semver Not specified
CNA Mattermost Mattermost affected 11.8.0 11.8.4 semver Not specified
CNA Mattermost Mattermost affected 11.7.0 11.7.7 semver Not specified
CNA Mattermost Mattermost affected 10.11.0 10.11.22 semver Not specified
CNA Mattermost Mattermost unaffected 11.10.0 Not specified
CNA Mattermost Mattermost unaffected 11.9.1 Not specified
CNA Mattermost Mattermost unaffected 11.8.5 Not specified
CNA Mattermost Mattermost unaffected 11.7.8 Not specified
CNA Mattermost Mattermost unaffected 10.11.23 Not specified

References

ReferenceSourceLinkTags
mattermost.com/security-updates [email protected] mattermost.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: 0x7oda7123 (en)

Additional Advisory Data

Solutions

CNA: Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8, 10.11.23 or higher.

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