{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.18+incompatible or later.","affected":[{"fixed":"10.11.18+incompatible","introduced":"10.11.0+incompatible"},{"fixed":"11.5.6+incompatible","introduced":"11.5.0+incompatible"},{"fixed":"11.6.3+incompatible","introduced":"11.6.0+incompatible"},{"fixed":"11.7.1+incompatible","introduced":"11.7.0+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-5139"],"ecosystem":"Go","epss":0.00287,"exploited":false,"fixed_versions":["10.11.18+incompatible","11.5.6+incompatible","11.6.3+incompatible","11.7.1+incompatible"],"ghsa_id":"GHSA-2g8v-grq3-hq2g","id":"tcs_01M5KGTYS9TM2Z8DWTDYYGEP37","modified_at":"2026-09-28T17:00:16.149696592Z","published_at":"2026-09-28T16:43:40Z","references":["https://osv.dev/vulnerability/GO-2026-6480","https://github.com/advisories/GHSA-2g8v-grq3-hq2g","https://nvd.nist.gov/vuln/detail/CVE-2026-5139","https://mattermost.com/security-updates"],"severity":{"label":"unknown"},"sources":[{"source":"osv","source_id":"GO-2026-6480","url":"https://osv.dev/vulnerability/GO-2026-6480"}],"summary":"Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler in github.com/mattermost/mattermost-server"}