CVE-2026-3636— Sanitize team member data returned by API

CVSS 4.3 · Medium EPSS 0.03% · P8 Updated May 22, 2026

Possible ATT&CK Techniques 1AI

Affected Version Matrix 9

Vendor	Product	Version Range	Status
Mattermost	Mattermost	`11.6.0≤ 11.6.0`	affected
		`11.5.0≤ 11.5.3`	affected
		`11.4.0≤ 11.4.4`	affected
		`10.11.0≤ 10.11.14`	affected
		`11.7.0`	unaffected
		`11.6.1`	unaffected
		`11.5.4`	unaffected
		`11.4.5`	unaffected
… +1 more rows

Get alerts for future matching vulnerabilitiesLog in to subscribe

I. Basic Information for CVE-2026-3636

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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

Sanitize team member data returned by API

Source: NVD (National Vulnerability Database)

Vulnerability Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data about team members roles via invoking various team API endpoints.. Mattermost Advisory ID: MMSA-2026-00626

Source: NVD (National Vulnerability Database)

CVSS Information

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

Source: NVD (National Vulnerability Database)

Vulnerability Type

信息暴露

Source: NVD (National Vulnerability Database)

Vulnerability Title

Mattermost 安全漏洞

Source: CNNVD (China National Vulnerability Database)

Vulnerability Description

Mattermost是美国Mattermost公司的一个开源协作平台。 Mattermost 11.6.0及之前的11.6.x版本、11.5.3及之前的11.5.x版本、11.4.4及之前的11.4.x版本和10.11.14及之前的10.11.x版本存在安全漏洞，该漏洞源于通过API向无权限用户返回团队成员数据时未进行清理，可能导致无权限用户通过调用各种团队API端点获取团队成员角色数据。

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	11.6.0 ~ 11.6.0	-

II. Public POCs for CVE-2026-3636

#	POC Description	Source Link	Shenlong Link

AI-Generated POCPremium

No public POC found.

III. Intelligence Information for CVE-2026-3636

请登录查看更多情报信息。

https://nvd.nist.gov/vuln/detail/CVE-2026-3636

Same Patch Batch · Mattermost · 2026-05-22 · 8 CVEs total

CVE-2026-5740	7.5 HIGH	Unauthenticated WebSocket binary frame causes denial of service in Mattermost Server
CVE-2026-4635	6.5 MEDIUM	Persistent notification timing attack causing server denial of service
CVE-2026-5755	6.5 MEDIUM	Denial of service via crafted TIFF file upload
CVE-2026-3473	5.9 MEDIUM	Improper file ownership validation in the Boards API allows unauthorised file access
CVE-2026-28735	5.4 MEDIUM	GitHub OAuth Scope Validation
CVE-2026-5308	4.9 MEDIUM	Missing request body size limits on Zoom plugin HTTP endpoints
CVE-2026-4646	4.3 MEDIUM	Insufficient input validation in GitHub plugin API causes denial of service

IV. Related Vulnerabilities

Same product: Mattermost

Same vendor: Mattermost

Same weakness: CWE-200

V. Comments for CVE-2026-3636

No comments yet

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

CVE-2026-3636— Sanitize team member data returned by API

Possible ATT&CK Techniques 1AI

Affected Version Matrix 9

I. Basic Information for CVE-2026-3636

Vulnerability Information

Vulnerability Title

Vulnerability Description

CVSS Information

Vulnerability Type

Vulnerability Title

Vulnerability Description

CVSS Information

Vulnerability Type

Affected Products

II. Public POCs for CVE-2026-3636

III. Intelligence Information for CVE-2026-3636

Same Patch Batch · Mattermost · 2026-05-22 · 8 CVEs total

IV. Related Vulnerabilities

V. Comments for CVE-2026-3636

Leave a comment