Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-16047— Board channel linking without read channel permission validation

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是美国Mattermost公司开源的一个开源协作平台。 Mattermost 11.7.6及之前的11.7.x版本、10.11.21及之前的10.11.x版本和11.8.3及之前的11.8.x版本存在授权问题漏洞，该漏洞源于在链接看板到频道前未验证用户是否具有该频道的读取权限，可能导致经过身份验证的攻击者通过创建、修补、导入或批量创建带有任意channelId的看板来发现同一团队中私有频道的成员。

CVSS 4.3 · Medium EPSS 0.16% · P6

Possible ATT&CK Techniques 1 AI

T1530 · Data from Cloud Storage

Affected Version Matrix 7

VendorProduct Version RangeStatus
Mattermost Mattermost 11.7.0≤ 11.7.6 affected
10.11.0≤ 10.11.21 affected
11.8.0≤ 11.8.3 affected
11.9.0 unaffected
11.7.7 unaffected
10.11.22 unaffected
11.8.4 unaffected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-16047

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Board channel linking without read channel permission validation
Source: CVE Program / CVE List V5
Vulnerability Description
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制缺失
Source: CVE Program / CVE List V5
Vulnerability Title
Mattermost 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mattermost是美国Mattermost公司开源的一个开源协作平台。 Mattermost 11.7.6及之前的11.7.x版本、10.11.21及之前的10.11.x版本和11.8.3及之前的11.8.x版本存在授权问题漏洞，该漏洞源于在链接看板到频道前未验证用户是否具有该频道的读取权限，可能导致经过身份验证的攻击者通过创建、修补、导入或批量创建带有任意channelId的看板来发现同一团队中私有频道的成员。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Mattermost Mattermost 11.7.0 ~ 11.7.6 -

II. Public POCs for CVE-2026-16047

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-16047

请登录查看更多情报信息。

Same Patch Batch · Mattermost · 2026-08-17 · 13 CVEs total

CVE-2026-9816 8.3 HIGH Insufficient server-side validation of board member role fields permits privilege escalati
CVE-2026-9859 6.5 MEDIUM Mattermost Boards plugin didn’t enforce role-based authorization on board channel link all
CVE-2026-10080 6.5 MEDIUM Boards plugin panics on WebSocket command with non-string field types
CVE-2026-10527 6.3 MEDIUM Boards plugin retains Board Admin rights for users demoted to System Guest
CVE-2026-16048 6.3 MEDIUM Channel member roles accept out-of-scope roles
CVE-2026-15754 4.2 MEDIUM Missing per-channel team-scope check in ABAC access control policy unassign allows cross-t
CVE-2026-16044 3.9 LOW Insufficient validation of guest board admin privileges on archive import
CVE-2026-16049 3.9 LOW _GitLab Plugin allows cross-channel post injection and phishing via missing channel permis
CVE-2026-75587 3.6 LOW Plaintext pre-auth secret exposure via Desktop App diagnostics report
CVE-2026-9693 3.5 LOW Mattermost thread memberships persist after team removal, exposing private channel thread
CVE-2026-16046 3.5 LOW Missing run-state validation on finished playbook runs
CVE-2026-16045 2.7 LOW Delegated OAuth tokens could revoke unrelated OAuth application authorizations

IV. Related Vulnerabilities

Same product: Mattermost
Same vendor: Mattermost
Same weakness: CWE-862

V. Comments for CVE-2026-16047

No comments yet

Leave a comment