{"id":"CVE-2026-18795","aliases":["EUVD-2026-102813","GHSA-c5qm-9j4f-82mg"],"status":"published","title":"Missing server side validation allowed user to quarantine a DM and GM post","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","severity":{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.0015,"percentile":0.04205,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-862"],"published":"2026-10-16T07:01:22Z","modified":"2026-10-31T02:49:00Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18795","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-c5qm-9j4f-82mg"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18795.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-18795","title":"Missing server side validation allowed user to quarantine a DM and GM post","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","status":"published","published":"2026-10-16T07:01:22.549Z","modified":"2026-10-16T11:59:42.771Z","cvss":[{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:20:12.60856Z"}],"euvd":[{"id":"EUVD-2026-102813","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","status":"published","published":"2026-10-16T07:01:22Z","modified":"2026-10-16T11:59:42Z","cvss":[{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium"}],"updated_at":"2026-11-02T17:00:06.126239Z"}],"ghsa":[{"id":"GHSA-c5qm-9j4f-82mg","title":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail...","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","status":"published","published":"2026-10-16T09:30:28Z","modified":"2026-10-16T09:30:34Z","cvss":[{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:13:51.12467Z"}],"nvd":[{"id":"CVE-2026-18795","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","status":"published","published":"2026-10-16T07:17:12.407Z","modified":"2026-10-29T18:08:37.923Z","cvss":[{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:12:59.751798Z"}],"osv":[{"id":"CVE-2026-18795","title":"Missing server side validation allowed user to quarantine a DM and GM post","description":"Mattermost versions 11.10.x \u003c= 11.10.0, 11.7.x \u003c= 11.7.9, 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756","status":"published","published":"2026-10-16T07:01:22.549Z","modified":"2026-10-31T02:49:00.767219806Z","cvss":[{"version":"3.1","score":6.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:44:58.024074Z"}]}}