{"id":"CVE-2026-96259","title":"Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 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 …","summary":"Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 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 …","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N","cwe":["CWE-918"],"vendor":"Mattermost","product":"Mattermost","affected":["Mattermost >= 11.9.0 <= 11.9.1","Mattermost >= 11.8.0 <= 11.8.5","Mattermost >= 11.7.0 <= 11.7.10","Mattermost >= 11.10.0 <= 11.10.1"],"published":"2026-09-22","updated":"2026-09-22","sourceUpdated":"2026-09-22T21:17:34.910","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-96259","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-22T21:11:40.323Z","slug":"CVE-2026-96259","body":"## Overview\n\nMattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 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\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}