{"id":"CVE-2025-49222","aliases":["EUVD-2025-25418","GHSA-q453-638c-h4mr","GO-2025-3904"],"status":"published","title":"Mattermost Shared Channel Upload Type Validation Bypass","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","severity":{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00301,"percentile":0.23096,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-434"],"published":"2025-08-21T07:59:45Z","modified":"2026-11-07T02:48:20Z","fixes":[{"ecosystem":"Go","package":"github.com/mattermost/mattermost-server","fixed_in":["10.8.4","10.5.9","9.11.18","10.9.3","10.10.1","9.11.18+incompatible","10.5.9+incompatible","10.8.4+incompatible","10.9.3+incompatible","10.10.1+incompatible"],"sources":["ghsa","osv"]},{"ecosystem":"Go","package":"github.com/mattermost/mattermost/server/v8","fixed_in":["8.0.0-20250708173752-d6b35c41f0ae5"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"10.8.0"},{"last_affected":"10.8.3"},{"fixed":"10.8.4"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"10.5.0"},{"last_affected":"10.5.8"},{"fixed":"10.5.9"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"9.11.0"},{"last_affected":"9.11.17"},{"fixed":"9.11.18"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"10.9.0"},{"last_affected":"10.9.2"},{"fixed":"10.9.3"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"10.10.0"},{"last_affected":"10.10.0"},{"fixed":"10.10.1"}]}],"versions":["10.10.0"]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost/server/v8","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.0-20250708173752-d6b35c41f0ae5"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.39.3"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v6","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.7.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"10.8.0"},{"fixed":"10.8.4"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"10.5.0"},{"fixed":"10.5.9"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"9.11.0"},{"fixed":"9.11.18"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"10.9.0"},{"fixed":"10.9.3"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"10.10.0"},{"fixed":"10.10.1"}]}],"versions":["10.10.0"]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost/server/v8","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"8.0.0-20250708173752-d6b35c41f0ae5"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v5","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"5.39.3"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v6","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"5.7.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server","ranges":[{"type":"SEMVER","events":[{"introduced":"9.11.0+incompatible"},{"fixed":"9.11.18+incompatible"},{"introduced":"10.5.0+incompatible"},{"fixed":"10.5.9+incompatible"},{"introduced":"10.8.0+incompatible"},{"fixed":"10.8.4+incompatible"},{"introduced":"10.9.0+incompatible"},{"fixed":"10.9.3+incompatible"},{"introduced":"10.10.0+incompatible"},{"fixed":"10.10.1+incompatible"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v5","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost-server/v6","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mattermost/mattermost/server/v8","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]}],"products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["Vendor Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-49222","tags":["advisory"]},{"url":"https://pkg.go.dev/vuln/GO-2025-3904","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q453-638c-h4mr","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/49xxx/CVE-2025-49222.json","tags":["advisory"]},{"url":"https://github.com/mattermost/mattermost","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2025-49222","title":"Mattermost Shared Channel Upload Type Validation Bypass","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T07:59:45.057Z","modified":"2025-08-21T13:57:13.759Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:32:25.186422Z"}],"euvd":[{"id":"EUVD-2025-25418","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T07:59:45Z","modified":"2025-08-21T13:57:13Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T20:31:55.037702Z"}],"ghsa":[{"id":"GHSA-q453-638c-h4mr","title":"Mattermost Fails to Validate Remote Cluster Upload Sessions","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T09:30:21Z","modified":"2025-08-29T20:58:15Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:38:55.953734Z"}],"nvd":[{"id":"CVE-2025-49222","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T08:15:30.177Z","modified":"2026-06-17T09:30:56.957Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:11:25.261243Z"}],"osv":[{"id":"CVE-2025-49222","title":"Mattermost Shared Channel Upload Type Validation Bypass","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T07:59:45.057Z","modified":"2026-11-07T02:48:20.481667329Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-07T03:07:57.2097Z"},{"id":"GHSA-q453-638c-h4mr","title":"Mattermost Fails to Validate Remote Cluster Upload Sessions","description":"Mattermost versions 10.8.x \u003c= 10.8.3, 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17, 10.9.x \u003c= 10.9.2, 10.10.x \u003c= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.","status":"published","published":"2025-08-21T09:30:21Z","modified":"2025-08-29T20:58:14Z","cvss":[{"version":"3.1","score":6.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T15:46:54.055966Z"},{"id":"GO-2025-3904","title":"Mattermost Fails to Validate Remote Cluster Upload Sessions in github.com/mattermost/mattermost-server","description":"Mattermost Fails to Validate Remote Cluster Upload Sessions in github.com/mattermost/mattermost-server.\n\nNOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.\n\n(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)\n\nThe additional affected modules and versions are: github.com/mattermost/mattermost/server/v8 before v8.0.0-20250708173752-d6b35c41f0ae5.","status":"published","published":"2025-08-29T14:52:20Z","modified":"2026-03-03T04:56:51.728076Z","updated_at":"2026-11-02T15:47:01.728182Z"}]}}