{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.14+incompatible or later.","affected":[{"fixed":"10.11.14+incompatible","introduced":"10.11.0+incompatible"},{"fixed":"11.5.2+incompatible","introduced":"11.5.0+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-6333"],"ecosystem":"Go","epss":0.00137,"exploited":false,"fixed_versions":["10.11.14+incompatible","11.5.2+incompatible"],"ghsa_id":"GHSA-vqp5-2mrp-qqxg","id":"tcs_01M5KGP1ZG0B9WJGQ56NAJYDY0","modified_at":"2026-06-25T23:01:38.693940001Z","published_at":"2026-06-25T22:34:38Z","references":["https://osv.dev/vulnerability/GO-2026-5671","https://github.com/advisories/GHSA-vqp5-2mrp-qqxg","https://nvd.nist.gov/vuln/detail/CVE-2026-6333","https://github.com/mattermost/mattermost/commit/e738016c592045e14bf926eafaeda6f8521def6d","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":5},"sources":[{"source":"osv","source_id":"GO-2026-5671","url":"https://osv.dev/vulnerability/GO-2026-5671"},{"source":"nvd","source_id":"CVE-2026-6333","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6333"}],"summary":"Mattermost doesn't validate the Host header when constructing response URLs for custom slash command in github.com/mattermost/mattermost-server"}