{"id":"CVE-2026-93849","title":"Mattermost allows authenticated users to trigger excessive memory allocation via crafted msgpack binary WebSocket frames","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 Mattermost fail to apply allocation limits to the byte-string decode paths in its WebSocket msgpack decoder, which allows an authenticated remo…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-789"],"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"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-26T15:32:42.705205Z"},"published":"2026-10-26","updated":"2026-10-26","sourceUpdated":"2026-10-26T16:46:45.736Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93849","references":[{"url":"https://mattermost.com/security-updates","label":"MMSA-2026-00768"}],"tags":["cve.org"],"ingestedAt":"2026-10-26T15:29:30.533Z","slug":"CVE-2026-93849","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 Mattermost fail to apply allocation limits to the byte-string decode paths in its WebSocket msgpack decoder, which allows an authenticated remote attacker to cause excessive server memory allocation via a crafted binary WebSocket frame declaring a Bin32 payload length of up to 4,294,967,295 bytes.. Mattermost Advisory ID: MMSA-2026-00768\n\n## Affected\n\n- `Mattermost >= 11.9.0 <= 11.9.1`\n- `Mattermost >= 11.8.0 <= 11.8.5`\n- `Mattermost >= 11.7.0 <= 11.7.10`\n- `Mattermost >= 11.10.0 <= 11.10.1`\n\n## Remediation\n\nUpdate Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}