CVE-2026-6347

Name: CVE-2026-6347
Creator: NVD / NIST
Published: 2026-05-18T09:16:24.143+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.6/10EPSS 0.26%

Last modified Jun 17, 2026

CVE-2026-6347 is a high-severity vulnerability rated 7.6/10 on the CVSS scale. 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. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

7.6/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:L

EPSS Probability

0.26%

16.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	>= 10.11.0, < 10.11.14
Mattermost	Mattermost Server	>= 11.4.0, < 11.4.4
Mattermost	Mattermost Server	>= 11.5.0, < 11.5.2

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: May 18, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-6347?

How severe is CVE-2026-6347?

CVE-2026-6347 has a CVSS score of 7.6/10 (HIGH severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2026-6347?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-6347?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST