Mattermost is grouping calls in the /metrics endpoint by id and reports that id in the response. Since this id is the channelID, the public /metrics endpoint is revealing channelIDs.
{
"nvd_published_at": "2023-12-06T09:15:09Z",
"severity": "MODERATE",
"github_reviewed": true,
"cwe_ids": [
"CWE-200"
],
"github_reviewed_at": "2023-12-08T21:57:14Z"
}