{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.18 or later.","affected":[{"fixed":"11.7.1","introduced":"11.7.0"},{"fixed":"11.6.3","introduced":"11.6.0"},{"fixed":"11.5.6","introduced":"11.5.0"},{"fixed":"10.11.18","introduced":"10.11.0"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-6673"],"ecosystem":"Go","epss":0.00299,"exploited":false,"fixed_versions":["11.7.1","11.6.3","11.5.6","10.11.18"],"ghsa_id":"GHSA-jqgv-39mg-7c2r","id":"tcs_01M5KFENHVNH5Q6GRK4CSWX33Y","modified_at":"2026-09-28T17:11:11.735586346Z","published_at":"2026-06-22T15:30:45Z","references":["https://osv.dev/vulnerability/GHSA-jqgv-39mg-7c2r","https://nvd.nist.gov/vuln/detail/CVE-2026-6673","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":6.4},"sources":[{"source":"osv","source_id":"GHSA-jqgv-39mg-7c2r","url":"https://osv.dev/vulnerability/GHSA-jqgv-39mg-7c2r"}],"summary":"Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret"}