Mattermost Plugins up to 11.5.1 Group authorization

CVSS Meta Temp Score
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability has been found in Mattermost Plugins up to 11.5.1 and classified as problematic. Affected is an unknown function of the component Group Handler. The manipulation leads to authorization. This vulnerability is documented as CVE-2026-6342. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Mattermost Plugins up to 11.5.1 and classified as problematic. This issue affects an unknown part of the component Group Handler. 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 integrity. The summary by CVE is:

Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601

The weakness was released by eahmed. It is possible to read the advisory at mattermost.com. The identification of this vulnerability is CVE-2026-6342 since 04/15/2026. 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 10.11.14, 11.4.4, 11.5.2 or 11.6.0 eliminates this vulnerability.

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

Productinfo

Type

Vendor

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
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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: Plugins 10.11.14/11.4.4/11.5.2/11.6.0

Timelineinfo

04/15/2026 CVE reserved
05/18/2026 +33 days Advisory disclosed
05/18/2026 +0 days VulDB entry created
05/18/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: eahmed
Status: Confirmed

CVE: CVE-2026-6342 (🔒)
GCVE (CVE): GCVE-0-2026-6342
GCVE (VulDB): GCVE-100-364451

Entryinfo

Created: 05/18/2026 10:03
Changes: 05/18/2026 10:03 (65)
Complete: 🔍
Cache ID: 216::103

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