Mattermost up to 10.11.13/11.4.3/11.5.1 Configuration information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Mattermost up to 10.11.13/11.4.3/11.5.1. This affects an unknown function of the component Configuration Handler. Such manipulation leads to information disclosure. This vulnerability is referenced as CVE-2026-6346. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.13/11.4.3/11.5.1 and classified as problematic. Affected by this issue is an unknown code block of the component Configuration Handler. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. CVE summarizes:

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields before including them in support packet generation, which allows a Mattermost System Admin or any party with access to a support packet to obtain sensitive credentials in plaintext via downloading a support packet from the System Console.. Mattermost Advisory ID: MMSA-2026-00607

The weakness was published by Edgar Bellot Micó. The advisory is shared for download at mattermost.com. This vulnerability is handled as CVE-2026-6346 since 04/15/2026. The exploitation is known to be easy. The attack may be launched remotely. The exploitation requires an enhanced level of successful authentication. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1592.

The vulnerability scanner Nessus provides a plugin with the ID 316492 (Mattermost Server 10.11.x <= 10.11.13 / 11.4.x <= 11.4.3 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00573 / MMSA-2026-00576 / MMSA-2026-00591 / MMSA-2026-00605 / MMSA-2026-00607 / MMSA-2026-00608 / MMSA-2026-00614 / MMSA-2026-00627)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 10.11.14, 11.4.4, 11.5.2 or 11.6.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (316492) and EUVD (EUVD-2026-30754). 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: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 2.7
VulDB Temp Score: 2.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.7
CNA Vector (Mattermost): 🔒

CVSSv2info

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

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / 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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Nessus ID: 316492
Nessus Name: Mattermost Server 10.11.x <= 10.11.13 / 11.4.x <= 11.4.3 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00573 / MMSA-2026-00576 / MMSA-2026-00591 / MMSA-2026-00605 / MMSA-2026-00607 / MMSA-2026-00608 / MMSA-2026-00614 / MMSA-2026-00627)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 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
05/23/2026 +5 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: Edgar Bellot Micó
Status: Confirmed

CVE: CVE-2026-6346 (🔒)
GCVE (CVE): GCVE-0-2026-6346
GCVE (VulDB): GCVE-100-364460
EUVD: 🔒

Entryinfo

Created: 05/18/2026 12:25
Updated: 05/23/2026 11:11
Changes: 05/18/2026 12:25 (65), 05/18/2026 15:34 (1), 05/23/2026 11:11 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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