{"id":"CVE-2026-9708","title":"Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to…","summary":"Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to…","severity":"medium","cvss":4.9,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N","cwe":["CWE-639"],"published":"2026-07-13","updated":"2026-07-13","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-9708","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd"],"ingestedAt":"2026-07-13T12:26:58.193Z","epss":0.00361,"epssPercentile":0.29755,"slug":"CVE-2026-9708","body":"## Overview\n\nMattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to create posts or direct messages attributed to another user via crafted incoming webhook configuration and payloads.. Mattermost Advisory ID: MMSA-2026-00683\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":27,"depthScoreParts":{"impact":27,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}