Information Exposure Affecting github.com/mattermost/mattermost/server/channels/app/slashcommands package, versions <10.11.11>=11.2.0-rc1 <11.2.3>=11.3.0-rc1 <11.3.1
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-GITHUBCOMMATTERMOSTMATTERMOSTSERVERCHANNELSAPPSLASHCOMMANDS-15702109
- published20 Mar 2026
- disclosed16 Mar 2026
- creditwinfunc
Introduced: 16 Mar 2026
CVE-2026-21386 Â (opens in a new tab)How to fix?
Upgrade github.com/mattermost/mattermost/server/channels/app/slashcommands to version 10.11.11, 11.2.3, 11.3.1 or higher.
Overview
Affected versions of this package are vulnerable to Information Exposure via inconsistent error handling in the /mute command. An attacker can infer the existence of private channels they are not authorized to access by analyzing the differences in error messages returned for nonexistent versus private channels.