{"action":"No fix published. Pin and monitor.","affected":[{"introduced":"0"}],"component":"github.com/mattermost/mattermost-server/v5","cve_ids":["CVE-2026-28759"],"ecosystem":"Go","epss":0.00152,"exploited":false,"fixed_versions":[],"ghsa_id":"GHSA-8h9w-w78c-vvr3","id":"tcs_01M5KGK11WVP21MYCXPH7W0GZ0","modified_at":"2026-06-25T19:45:26.220689565Z","published_at":"2026-06-25T18:43:15Z","references":["https://osv.dev/vulnerability/GO-2026-5256","https://github.com/advisories/GHSA-8h9w-w78c-vvr3","https://nvd.nist.gov/vuln/detail/CVE-2026-28759","https://github.com/mattermost/mattermost/commit/8738f8c4b3d42b2b687a6231e72f313357a2e891","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.3},"sources":[{"source":"osv","source_id":"GO-2026-5256#Go/github.com/mattermost/mattermost-server/v5","url":"https://osv.dev/vulnerability/GO-2026-5256"},{"source":"nvd","source_id":"CVE-2026-28759","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-28759"}],"summary":"Mattermost does not verify remote cluster channel access when processing shared channel membership removals in github.com/mattermost/mattermost-server"}