Mattermost up to 10.11.10/11.3.x API 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, was found in Mattermost up to 10.11.10/11.3.x. This vulnerability affects unknown code of the component API Endpoint. Such manipulation leads to authorization. This vulnerability is uniquely identified as CVE-2026-26230. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.10/11.3.x. It has been rated as problematic. Affected by this issue is some unknown functionality of the component API Endpoint. 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. CVE summarizes:

Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531

The weakness was disclosed by hackit_bharat. The advisory is shared for download at mattermost.com. This vulnerability is handled as CVE-2026-26230 since 02/13/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are required for exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 10.11.11 or 11.4.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-12518). Once again VulDB remains the best 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: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.7
VulDB Temp Score: 4.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.8
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

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 10.11.11/11.4.0

Timelineinfo

02/13/2026 CVE reserved
03/16/2026 +31 days Advisory disclosed
03/16/2026 +0 days VulDB entry created
03/21/2026 +5 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: hackit_bharat
Status: Confirmed

CVE: CVE-2026-26230 (🔒)
GCVE (CVE): GCVE-0-2026-26230
GCVE (VulDB): GCVE-100-351332
EUVD: 🔒

Entryinfo

Created: 03/16/2026 22:28
Updated: 03/21/2026 16:36
Changes: 03/16/2026 22:28 (64), 03/17/2026 03:36 (1), 03/21/2026 16:36 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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