Mattermost up to 10.11.13/11.4.3/11.5.1 Calls Plugin plaintext information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mattermost up to 10.11.13/11.4.3/11.5.1. Affected by this vulnerability is an unknown functionality of the component Calls Plugin. The manipulation of the argument plaintext leads to information disclosure. This vulnerability is listed as CVE-2026-6347. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.13/11.4.3/11.5.1. It has been rated as problematic. This issue affects an unknown functionality of the component Calls Plugin. The manipulation of the argument plaintext 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. The summary by CVE is:

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 in the Mattermost Calls plugin which allows an attacker with access to a support packet to obtain TURN server credentials via the plaintext values present in the exported plugin configuration.. Mattermost Advisory ID: MMSA-2026-00605

The weakness was presented by Edgar Bellot Micó. It is possible to read the advisory at mattermost.com. The identification of this vulnerability is CVE-2026-6347 since 04/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are necessary for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

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-2026-30752). 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: 5.1
VulDB Meta Temp Score: 5.1

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

CNA Base Score: 7.6
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-2026-6347 (🔒)
GCVE (CVE): GCVE-0-2026-6347
GCVE (VulDB): GCVE-100-364463
EUVD: 🔒

Entryinfo

Created: 05/18/2026 12:27
Updated: 05/23/2026 11:11
Changes: 05/18/2026 12:27 (66), 05/18/2026 15:34 (1), 05/23/2026 11:11 (2)
Complete: 🔍
Cache ID: 216::103

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

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