Mattermost up to 11.6.x Crafted API authorization

CVSS Meta Temp Score
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CTI Interest Score
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7.4$0-$5k4.20-

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.15/10.11.16/11.5.4/11.6.1/11.6.x. It has been classified as critical. Affected is an unknown function of the component Crafted API. The manipulation leads to authorization. This vulnerability is referenced as CVE-2026-7387. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.15/10.11.16/11.5.4/11.6.1/11.6.x. It has been rated as critical. This issue affects an unknown code block of the component Crafted API. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests.. Mattermost Advisory ID: MMSA-2026-00665

The weakness was published by winfunc. It is possible to read the advisory at mattermost.com. The identification of this vulnerability is CVE-2026-7387 since 04/29/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 10.11.16, 10.11.17, 11.5.5, 11.6.2 or 11.7.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36503). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.4

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.8
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-863 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.16/10.11.17/11.5.5/11.6.2/11.7.0

Timelineinfo

04/29/2026 CVE reserved
06/12/2026 +44 days Advisory disclosed
06/12/2026 +0 days VulDB entry created
06/12/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: winfunc
Status: Confirmed

CVE: CVE-2026-7387 (🔒)
GCVE (CVE): GCVE-0-2026-7387
GCVE (VulDB): GCVE-100-370655
EUVD: 🔒

Entryinfo

Created: 06/12/2026 19:35
Updated: 06/12/2026 22:14
Changes: 06/12/2026 19:35 (64), 06/12/2026 22:14 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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