{"action":"Upgrade github.com/mattermost/mattermost-server to 4.1.2+incompatible or later.","affected":[{"fixed":"4.1.2+incompatible","introduced":"0"},{"fixed":"4.2.1+incompatible","introduced":"4.2.0+incompatible"},{"fixed":"4.3.0+incompatible","introduced":"4.3.0-rc1+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2017-18877"],"ecosystem":"Go","epss":0.0069,"exploited":false,"fixed_versions":["4.1.2+incompatible","4.2.1+incompatible","4.3.0+incompatible"],"ghsa_id":"GHSA-9x8x-w6g5-hx4w","id":"tcs_01M5KGC67X7WEZKCPJ7CFSTZ1N","modified_at":"2026-03-03T04:57:45.560872Z","published_at":"2025-12-08T21:31:36Z","references":["https://osv.dev/vulnerability/GO-2025-4190","https://github.com/advisories/GHSA-9x8x-w6g5-hx4w","https://nvd.nist.gov/vuln/detail/CVE-2017-18877","https://mattermost.com/security-updates"],"severity":{"label":"unknown"},"sources":[{"source":"osv","source_id":"GO-2025-4190","url":"https://osv.dev/vulnerability/GO-2025-4190"}],"summary":"Mattermost Server is vulnerable to XSS attacks against an OAuth 2.0 allow/deny page in github.com/mattermost/mattermost-server"}