{"action":"Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20260107144005-c7f6efdfb035 or later.","affected":[{"fixed":"5.3.2-0.20260107144005-c7f6efdfb035","introduced":"0"},{"fixed":"10.11.11","introduced":"10.11.0-rc1"},{"fixed":"11.2.3","introduced":"11.2.0-rc1"},{"fixed":"11.3.1","introduced":"11.3.0-rc1"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-4265"],"ecosystem":"Go","epss":0.00379,"exploited":false,"fixed_versions":["5.3.2-0.20260107144005-c7f6efdfb035","10.11.11","11.2.3","11.3.1"],"ghsa_id":"GHSA-xpvf-6qcc-9jqc","id":"tcs_01M5KFSJYEDEGDBAZ1XEHT8808","modified_at":"2026-03-23T18:56:04.837800Z","published_at":"2026-03-16T15:30:46Z","references":["https://osv.dev/vulnerability/GHSA-xpvf-6qcc-9jqc","https://nvd.nist.gov/vuln/detail/CVE-2026-4265","https://github.com/mattermost/mattermost/commit/c7f6efdfb035490f494b3177996ee5f4b278c988","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.3},"sources":[{"source":"osv","source_id":"GHSA-xpvf-6qcc-9jqc#Go/github.com/mattermost/mattermost-server","url":"https://osv.dev/vulnerability/GHSA-xpvf-6qcc-9jqc"}],"summary":"Mattermost fails to validate team-specific upload_file permissions"}