Mattermost doesn't sanitize sensitive configuration fields in the Mattermost Calls plugin

CVE-2026-6347 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Browse source ↗
Published (advisory)
2026-05-18 09:31:48 UTC
Updated
2026-06-01 15:44:51 UTC
GitHub reviewed
2026-06-01 15:44:48 UTC
NVD published
2026-05-18

EPSS Score

Score Percentile
0.05% 16.59%

CVSS Scores

Base score Version Severity Vector
7.6 3.1 —
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.

Identifiers

Type Value
GHSA GHSA-82j6-4fq7-fx62 ↗
CVE CVE-2026-6347 ↗

CWEs

CWE id Name
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Affected packages (4)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/mattermost/mattermost-server >= 11.5.0, < 11.5.2 11.5.2 —
go github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.14 10.11.14 —
go github.com/mattermost/mattermost-server >= 11.4.0, < 11.4.4 11.4.4 —
go github.com/mattermost/mattermost-plugin-calls < 1.12.0-rc2 1.12.0-rc2 —

References

cvelogic Threat Intelligence