{"id":"CVE-2026-10819","aliases":["EUVD-2026-49254","GHSA-qf49-6jm2-h67m"],"status":"published","title":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","description":"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","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0042,"percentile":0.36651,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-409"],"published":"2026-07-27T14:15:25Z","modified":"2026-10-28T02:30:48Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10819","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qf49-6jm2-h67m"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10819.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-10819","title":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","description":"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","status":"published","published":"2026-07-27T14:15:25Z","modified":"2026-07-27T15:05:28.394Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T13:40:12.486331Z"}],"euvd":[{"id":"EUVD-2026-49254","description":"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","status":"published","published":"2026-07-27T14:15:25Z","modified":"2026-07-27T15:05:28Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T18:02:34.216106Z"}],"ghsa":[{"id":"GHSA-qf49-6jm2-h67m","title":"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...","description":"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","status":"published","published":"2026-07-27T15:32:31Z","modified":"2026-07-27T15:32:39Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T15:09:50.782117Z"}],"nvd":[{"id":"CVE-2026-10819","description":"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","status":"published","published":"2026-07-27T15:16:46.77Z","modified":"2026-08-03T15:23:50.49Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:12:32.830533Z"}],"osv":[{"id":"CVE-2026-10819","title":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","description":"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","status":"published","published":"2026-07-27T14:15:25Z","modified":"2026-10-28T02:30:48.485454996Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T15:44:54.933106Z"}]}}