{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.15+incompatible or later.","affected":[{"fixed":"10.11.15+incompatible","introduced":"10.11.0+incompatible"},{"fixed":"11.4.5+incompatible","introduced":"11.4.0+incompatible"},{"fixed":"11.5.4+incompatible","introduced":"11.5.0+incompatible"},{"fixed":"11.6.1+incompatible","introduced":"11.6.0+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-4915"],"ecosystem":"Go","epss":0.00277,"exploited":false,"fixed_versions":["10.11.15+incompatible","11.4.5+incompatible","11.5.4+incompatible","11.6.1+incompatible"],"ghsa_id":"GHSA-5gmf-x7hg-97wf","id":"tcs_01M5KGQ7ZFFY3SHA6T71BJQZ7Z","modified_at":"2026-07-07T16:01:34.743955987Z","published_at":"2026-07-07T15:26:32Z","references":["https://osv.dev/vulnerability/GO-2026-5845","https://github.com/advisories/GHSA-5gmf-x7hg-97wf","https://nvd.nist.gov/vuln/detail/CVE-2026-4915","https://github.com/mattermost/mattermost/commit/faa7d75b4ea041701e97948f8aa1332e3626a39a","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":6.5},"sources":[{"source":"osv","source_id":"GO-2026-5845","url":"https://osv.dev/vulnerability/GO-2026-5845"},{"source":"nvd","source_id":"CVE-2026-4915","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4915"}],"summary":"Mattermost doesn't filter nil elements from outgoing webhook attachment payloads before processing in github.com/mattermost/mattermost-server"}