{"id":"CVE-2026-6333","title":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacke…","summary":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacke…","severity":"low","cvss":3.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N","cwe":["CWE-918"],"vendor":"mattermost","product":"mattermost_server","affected":["mattermost_server >= 10.11.0, < 10.11.14","mattermost_server >= 11.5.0, < 11.5.2"],"patched":["mattermost_server 11.5.2"],"published":"2026-05-18","updated":"2026-10-14","sourceUpdated":"2026-10-14T20:10:00.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-6333","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd"],"epss":0.00224,"epssPercentile":0.12047,"ingestedAt":"2026-10-14T20:53:12.299Z","slug":"CVE-2026-6333","body":"## Overview\n\nMattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582\n\n## Affected\n\n- `mattermost_server >= 10.11.0, < 10.11.14`\n- `mattermost_server >= 11.5.0, < 11.5.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `mattermost_server 11.5.2`","depth":"sunlit","depthScore":19,"depthScoreParts":{"impact":19.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}