Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0 Group Retrieval Endpoint authorization

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0. Affected by this vulnerability is an unknown functionality of the component Group Retrieval Endpoint. This manipulation causes authorization. This vulnerability appears as CVE-2026-3115. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0. Affected by this vulnerability is an unknown functionality of the component Group Retrieval Endpoint. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality. The summary by CVE is:

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594

The weakness was presented by winfunc. It is possible to read the advisory at mattermost.com. This vulnerability is known as CVE-2026-3115 since 02/24/2026. The exploitation appears to be easy. The attack can be launched remotely. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 10.11.11, 11.2.3, 11.3.2, 11.4.1 or 11.5.0 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
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

EPSS Score: 🔒
EPSS Percentile: 🔒

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 10.11.11/11.2.3/11.3.2/11.4.1/11.5.0

Timelineinfo

02/24/2026 CVE reserved
03/26/2026 +30 days Advisory disclosed
03/26/2026 +0 days VulDB entry created
03/26/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: winfunc
Status: Confirmed

CVE: CVE-2026-3115 (🔒)
GCVE (CVE): GCVE-0-2026-3115
GCVE (VulDB): GCVE-100-353683

Entryinfo

Created: 03/26/2026 19:02
Changes: 03/26/2026 19:02 (64)
Complete: 🔍
Cache ID: 216::103

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