CVE-2026-6347
High
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
SeverityHigh
CVSS7.6
Exploit probability19. percentile0.3%
Product
Mattermost Server
PublishedMay 18, 2026
First seenMay 18, 2026
Weakness typeCWE-200Sensitive information exposure
How to fix
Update
- mattermost mattermost_server10.11.14, 11.4.4, 11.5.2 or later
- github.com/mattermost/mattermost-server11.5.2, 10.11.14, 11.4.4, 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible or later
- github.com/mattermost/mattermost-plugin-calls1.12.0-rc2 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 10.11.0 ≤ v < 10.11.14, 11.4.0 ≤ v < 11.4.4, 11.5.0 ≤ v < 11.5.2 | 10.11.14, 11.4.4, 11.5.2 |
| github.com/mattermost/mattermost-serverGo | 11.5.0 ≤ v < 11.5.2, 10.11.0 ≤ v < 10.11.14, 11.4.0 ≤ v < 11.4.4, 10.11.0+incompatible ≤ v < 10.11.14+incompatible, 11.4.0+incompatible ≤ v < 11.4.4+incompatible, 11.5.0+incompatible ≤ v < 11.5.2+incompatible | 11.5.2, 10.11.14, 11.4.4, 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible |
| github.com/mattermost/mattermost-plugin-callsGo | v < 1.12.0-rc2 | 1.12.0-rc2 |
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