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CVE-2026-91181— Data Retention Teams Endpoint Leaks Private Team Invite ID

Quick assessment

Affected
Mattermost Mattermost
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Mattermost 版本 11.9.x（≤ 11.9.0）、11.8.x（≤ 11.8.4）、11.7.x（≤ 11.7.7）和 10.11.x（≤ 10.11.22）存在数据保留（Data Retention）相关接口中团队对象未充分净化的问题。该漏洞允许仅拥有“只读数据保留策略”权限的已认证用户，通过 接口获取私有团队的机密邀请 ID（invite_id）和邮箱地址，并借此未经授权加入该团队。 Mattermost 安全公告编号：MMSA-2026-00702

CVSS 6.5 · Medium
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I. Basic Information for CVE-2026-91181

Vulnerability Information
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Vulnerability Title
Data Retention Teams Endpoint Leaks Private Team Invite ID
Source: CVE Program / CVE List V5
Vulnerability Description
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
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Mattermost Mattermost 11.9.0 ~ 11.9.0 -

II. Public POCs for CVE-2026-91181

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III. Intelligence Information for CVE-2026-91181

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Same Patch Batch · Mattermost · 2026-09-14 · 16 CVEs total

CVE-2026-8821 7.1 HIGH Playbooks run owner channel membership permission bypass
CVE-2026-12985 6.8 MEDIUM Mattermost DCR redirect URI allowlist bypass via improper URL component validation
CVE-2026-15814 6.5 MEDIUM Uploading a crafted image causes excessive memory allocation in the Mattermost Server
CVE-2026-9812 6.5 MEDIUM Missing property field ownership validation in Playbooks run property update endpoint
CVE-2026-5132 6.5 MEDIUM Unbounded zlib decompression in Calls SDP WebSocket messages
CVE-2026-82920 5.5 MEDIUM Mattermost ABAC parent policy bypass via policy update endpoint
CVE-2026-10556 5.3 MEDIUM Unauthenticated webhook request with null notification entry could crash the Microsoft Cal
CVE-2026-10542 5.0 MEDIUM Playbooks channel action update validation issue
CVE-2026-11993 4.3 MEDIUM Fix authenticated members disabling file content indexing server-wide via extraction pool
CVE-2026-14344 4.3 MEDIUM Inconsistent authorization checks in Mattermost Boards endpoints
CVE-2026-14259 4.3 MEDIUM Board archive import bypasses team board creation permissions
CVE-2026-12882 4.3 MEDIUM Mattermost Markdown autolink parsing denial of service
CVE-2026-13417 4.3 MEDIUM Boards plugin denial of service via unvalidated block fields.properties
CVE-2026-86348 4.3 MEDIUM MS Calendar plugin: unrecovered handler panics from malformed post-action requests could c
CVE-2026-86349 4.3 MEDIUM Mattermost Server Algorithmic DoS via Unbounded Markdown Block Nesting

IV. Related Vulnerabilities

Same product: Mattermost
Same vendor: Mattermost
Same weakness: CWE-863

V. Comments for CVE-2026-91181

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