Authentication Bypass by Primary Weakness Affecting github.com/mattermost/mattermost/server/channels/app package, versions >=10.11.0-rc1 <10.11.14-rc1>=11.5.0-rc1 <11.5.2-rc1
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.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMMATTERMOSTMATTERMOSTSERVERCHANNELSAPP-16777270
- published20 May 2026
- disclosed18 May 2026
- creditDylan Haussermann
Introduced: 18 May 2026
CVE-2026-6334 (opens in a new tab)How to fix?
Upgrade github.com/mattermost/mattermost/server/channels/app to version 10.11.14-rc1, 11.5.2-rc1 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 authorization code redemption process. An attacker can gain unauthorized access to resources by redeeming authorization codes issued to a different client through a crafted token exchange request.