{"id":"CVE-2026-10819","summary":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","details":"Mattermost versions 11.6.x \u003c= 11.6.5, 10.11.x \u003c= 10.11.20, 11.8.x \u003c= 11.8.1, 11.7.x \u003c= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF uploaded as a custom emoji.. Mattermost Advisory ID: MMSA-2026-00695","modified":"2026-08-05T03:47:28.380289844Z","published":"2026-07-27T14:15:25Z","database_specific":{"unresolved_ranges":[{"extracted_events":[{"introduced":"11.6.0"},{"last_affected":"11.6.5"},{"introduced":"10.11.0"},{"last_affected":"10.11.20"},{"introduced":"11.8.0"},{"last_affected":"11.8.1"},{"introduced":"11.7.0"},{"last_affected":"11.7.4"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"Mattermost","cwe_ids":["CWE-409"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10819.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10819.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10819"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"5b955468ea1ea8b56c0fb10feb258a36a767d7bb"},{"fixed":"638007314e9dde1575d3caa167e1067b1c577204"},{"introduced":"d4f4e78835e86e2e76f76bfe797623076f5c9835"},{"fixed":"aa548ce407dac894c70983decc17fb263b1aa683"},{"introduced":"a9e574a82633915f22071f0d7ca2b006f249ec2a"},{"fixed":"1bada408cb657081218f37aa3a470ad30bdf3014"},{"introduced":"e8bd2b8a871cbeff6943bead62328478118188df"},{"fixed":"f4e6ebaf057b1d59bb735ee51f849624cf25b24d"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"10.11.0"},{"fixed":"10.11.21"},{"introduced":"11.6.0"},{"fixed":"11.6.6"},{"introduced":"11.7.0"},{"fixed":"11.7.5"},{"introduced":"11.8.0"},{"fixed":"11.8.2"}]}}],"versions":["v11.8.1","v11.7.4","v11.6.5","v11.7.3","v10.11.20","v11.8.0-rc5","v11.8.0","mattermost-redux@11.8.0","@mattermost/types@11.8.0","@mattermost/shared@11.8.0","@mattermost/client@11.8.0","v10.11.19","v11.6.4","v10.11.19-rc1","v11.7.2","v11.6.3","v10.11.18","v11.7.1","v11.6.2","v10.11.17","v10.11.16","v11.7.0","mattermost-redux@11.7.0","@mattermost/types@11.7.0","@mattermost/shared@11.7.0","@mattermost/client@11.7.0","v10.11.15-rc1","v10.11.15","v11.6.1-rc1","v11.6.1","v10.11.14","v11.6.0","v10.11.14-rc1","v10.11.13","v10.11.13-rc1","v10.11.12","v10.11.11-rc2","v10.11.11","v10.11.11-rc1","v10.11.10","v10.11.9","v10.11.9-rc1","v10.11.8","v10.11.7","v10.11.6","v10.11.5","v10.11.4-rc3","v10.11.4","v10.11.4-rc2","v10.11.4-rc1","v10.11.3","v10.11.2-rc2","v10.11.2","v10.11.2-rc1","v10.11.1","v10.11.1-rc1","v10.11.0-rc3","v10.11.0","mattermost-redux@10.11.0","@mattermost/types@10.11.0","@mattermost/client@10.11.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-10819.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}