Authorization Bypass Through User-Controlled Key Affecting github.com/mattermost/mattermost/server/channels/api4 package, versions >=10.11.0 <10.11.20>=11.6.0 <11.6.5>=11.7.0 <11.7.3>=11.8.0-rc1 <11.8.0-rc5
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Authorization Bypass Through User-Controlled Key vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-GOLANG-GITHUBCOMMATTERMOSTMATTERMOSTSERVERCHANNELSAPI4-17966787
- published14 Jul 2026
- disclosed13 Jul 2026
- creditUnknown
Introduced: 13 Jul 2026
NewCVE-2026-9708 (opens in a new tab)How to fix?
Upgrade github.com/mattermost/mattermost/server/channels/api4 to version 10.11.20, 11.6.5, 11.7.3, 11.8.0-rc5 or higher.
Overview
Affected versions of this package are vulnerable to Authorization Bypass Through User-Controlled Key via the incoming webhook process. An attacker can impersonate another user and create posts or direct messages attributed to them by crafting specific webhook configurations and payloads.