Authentication Bypass by Primary Weakness Affecting github.com/mattermost/mattermost/server/channels/app 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-rc4
Threat Intelligence
This vulnerability is trending on Twitter; this may indicate a growing threat.
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 applications- Snyk IDSNYK-GOLANG-GITHUBCOMMATTERMOSTMATTERMOSTSERVERCHANNELSAPP-17966785
- published14 Jul 2026
- disclosed13 Jul 2026
- creditUnknown
Introduced: 13 Jul 2026
CVE-2026-9571 (opens in a new tab)How to fix?
Upgrade github.com/mattermost/mattermost/server/channels/app to version 10.11.20, 11.6.5, 11.7.3, 11.8.0-rc4 or higher.
Overview
github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative
Affected versions of this package are vulnerable to Authentication Bypass by Primary Weakness in the OAuth refresh token grant process. An attacker can maintain unauthorized access by using a valid refresh token associated with a deactivated account.