{"id":"CVE-2026-96259","summary":"Mattermost server-side request forgery via OAuth endpoints configurable by a System Administrator","details":"Mattermost versions 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5, 11.7.x \u003c= 11.7.10, 11.10.x \u003c= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776","modified":"2026-10-09T02:47:42.233963852Z","published":"2026-09-22T20:34:20.872Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96259.json","unresolved_ranges":[{"extracted_events":[{"introduced":"11.9.0"},{"last_affected":"11.9.1"},{"introduced":"11.8.0"},{"last_affected":"11.8.5"},{"introduced":"11.7.0"},{"last_affected":"11.7.10"},{"introduced":"11.10.0"},{"last_affected":"11.10.1"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"Mattermost","cwe_ids":["CWE-918"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96259.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-96259"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"a9e574a82633915f22071f0d7ca2b006f249ec2a"},{"fixed":"062eb3ba0e0f265bd0bc78d8c5ce5df06b7b6bc8"},{"introduced":"583461af10fc9b2aef2871c722fc4376db695832"},{"fixed":"8ed7691c22159afec427468b8a866aeeaf59a12c"},{"introduced":"7f5bffb8cf3977db8237ce10158fa22aa0d2504f"},{"fixed":"3a01fa64e5c292bd2503de37160cae10e10096de"}],"database_specific":{"extracted_events":[{"introduced":"11.7.0"},{"fixed":"11.7.11"},{"introduced":"11.9.0"},{"fixed":"11.9.2"},{"introduced":"11.10.0"},{"fixed":"11.10.2"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*"}}],"versions":["v11.7.10","v11.10.1","v11.7.9","v11.9.1-rc1","v11.9.1","v11.10.0-rc3","v11.10.0","v11.7.8","v11.7.7","v11.9.0","mattermost-redux@11.9.0","@mattermost/types@11.9.0","@mattermost/shared@11.9.0","@mattermost/client@11.9.0","v11.7.6","v11.7.5-rc1","v11.7.5","v11.7.4","v11.7.3","v11.7.2","v11.7.1","v11.7.0","mattermost-redux@11.7.0","@mattermost/types@11.7.0","@mattermost/shared@11.7.0","@mattermost/client@11.7.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-96259.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N"}]}