CVE-2026-91181

medium

Mattermost 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 team…

Vendor / product: Mattermost — mattermost server

Mattermost 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

CVSS

6.5

6.5 (CVSS v3.1)

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

Severity source: NVD CVSS v3.1 (responsibledisclosure@mattermost.com)

Timeline (UTC)

Published: 2026-09-14 22:16

Modified: 2026-10-07 16:49

NVD status: Analyzed

Last synced 1 day ago

Verified against the source API 2026-10-27 06:53 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

mattermost / mattermost_server ≥10.11.0 <10.11.23, ≥11.7.0 <11.7.8, ≥11.8.0 <11.8.5, ≥11.9.0 <11.9.1

Weakness classification (CWE)

CWE-863

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

Vendor advisory: https://mattermost.com/security-updates

References

https://mattermost.com/security-updates responsibledisclosure@mattermost.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:53 UTC · record ↗

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CVE-2026-91181

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